Library Selection 10 - Imperato_McGinley...and T action for the gender identity masculinization

Since October 30th, 2003

Hit Counter

Library Selection 1 - Kruijver et al,2000 and others Abstracts and Free Full Papers
Library Selection 2 - Aphallia & Sissyboys
Library Selection 3 - Transsexual Hormone Therapy (HRT)
Library Selection 4 - Hormones and the primate Brain... humans and non humans... USA studies.
Library Selection 5 - FtM Transsexual, Aphallia & Micropenis
Library Selection 6 - AR testosterone-DHT selectivity; Transgenders and Crossdressers
Library Selection 7 - AR testosterone-DHT selectivity; Torres & Jurberg Hypothesis
Library Selection 8 - SF-1 and DAX-1 papers
Library Selection 9 - Dörner....and the brain sexual differentiation
Library Selection 10 - Imperato_McGinley...and T action for the gender identity masculinization
See here some scientific abstracts from Medline.
Access Medline Abstracts and Papers yourself directly.
See below some wonderful paper abstracts and sometimes FREE FULL PAPERS!.

Joan Imperato-McGinley is one of the most important researchers about gender identity formation, in my opinion, or the most important....because she discovered, studying 5-alfa-reductase deficiency syndrome, that hormones are important in GI differentiation. Children reared as John Money suggests, as females, do not learn to be females, because the hormones made their brains masculine during gestation, and later they showed they were males. Imperato-McGinley published it, but nobody believed her, because of Money's authority. Today we know, Joan and not John was right. Testosterone, and testosterone aromatization in primate brains, includding human, is fundamental for the GI differentiation to a male brain. The male brain is molded by testosterone action, and not DHT action. And surely not only by family and sex of rearing action.

1: Baillieres Clin Endocrinol Metab. 1998 Apr;12(1):83-113. Related Articles, Links

Natural potent androgens: lessons from human genetic models.

Zhu YS, Katz MD, Imperato-McGinley J.

Department of Medicine, Cornell University Medical College, New York, NY 10021, USA.

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase-3 (17 beta-HSD-3) deficiency and 5 alpha-reductase-2 (5 alpha-RD-2) deficiency provides natural human genetic models to elucidate androgen actions. To date, five 17 beta-HSD isozymes have been cloned that catalyse the oxidoreduction of androstenedione and testosterone and dihydrotestosterone (DHT), oestrone and oestradiol. Mutations in the isozyme 17 beta-HSD-3 gene are responsible for male pseudohermaphroditism due to 17 beta-HSD deficiency. The type 3 isozyme preferentially catalyses the reduction of androstenedione to testosterone and is primarily expressed in the testes. Fourteen mutations in the 17 beta-HSD-3 gene have been identified from different ethnic groups. Affected males with the 17 beta-HSD-3 gene defect have normal wolffian structures but ambiguous external genitalia at birth. Many are raised as girls but virilize at the time of puberty and adopt a male gender role. Some develop gynaecomastia at puberty, which appears to be related to the testosterone/oestradiol ratio. Two 5 alpha-reductase (5 alpha-RD) isozymes, types 1 and 2, have been identified, which convert testosterone to the more potent androgen DHT. Mutations in the 5 alpha-RD-2 gene cause male pseudohermaphroditism, and 31 mutations in the 5 alpha-RD-2 gene have been reported from various ethnic groups. Such individuals also have normal wolffian structure but ambiguous external genitalia at birth and are raised as girls. Virilization occurs at puberty, often with a gender role change. The prostate remains infantile and facial hair is decreased. Balding has not been reported.

Publication Types:
  • Review
  • Review, Tutorial

PMID: 9890063 [PubMed - indexed for MEDLINE]
1: J Clin Endocrinol Metab. 1998 Jun;83(6):1940-5. Related Articles, Links
Click here to read 
Study of a kindred with classic congenital adrenal hyperplasia: diagnostic challenge due to phenotypic variance.

Chin D, Speiser PW, Imperato-McGinley J, Dixit N, Uli N, David R, Oberfield SE.

Department of Pediatrics, New York University Medical Center, New York 10016, USA.

We sought to determine the concordance of the phenotype and genotype in a kindred with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The variation in phenotypic expression within this family underscores the difficulty of establishing the diagnosis in the absence of newborn screening, even with a heightened index of suspicion. Steroidogenic profiles were obtained for the three affected siblings. The available clinical history of the two affected aunts was retrieved. Genotyping was performed on several members of the kindred. Detailed sequencing of the entire CYP21 gene of two clinically dissimilar subjects in this family was undertaken to explore the possibility of other mutations or polymorphisms. PCR with ligase detection reaction analysis of CYP21 revealed that the affected family members III-2, III-3, III-4, II-3, and II-4, all were compound heterozygotes carrying the intron 2 point mutation known to interfere with splicing (nucleotide 656 A to G) and the exon 4 point mutation causing a nonconservative substitution of asparagine for isoleucine at codon 172 (I172N). Detailed sequencing of the gene was performed for the two most phenotypically dissimilar subjects. A single silent polymorphism was found in the third nucleotide for codon 248 in patient II-4, but not in patient III-4, and no additional mutations were found. Classic congenital adrenal hyperplasia remains a difficult diagnosis to make in the absence of newborn screening because of the variability of phenotypic expression. Likewise, the variable degree of genital ambiguity in affected females in this family serves to question universal advocacy of prenatal steroid treatment in pregnancies at risk for congenital adrenal hyperplasia. Extensive molecular exploration did not provide an explanation of the phenotypic heterogeneity and supports the possibility of influences other than the CYP21 gene for the observed divergence.

PMID: 9626123 [PubMed - indexed for MEDLINE]
1: J Clin Endocrinol Metab. 1998 Feb;83(2):560-9. Related Articles, Links
Click here to read 
The identification of 5 alpha-reductase-2 and 17 beta-hydroxysteroid dehydrogenase-3 gene defects in male pseudohermaphrodites from a Turkish kindred.

Can S, Zhu YS, Cai LQ, Ling Q, Katz MD, Akgun S, Shackleton CH, Imperato-McGinley J.

Department of Medicine, Cornell University Medical College, New York, New York 10021, USA.

Male pseudohermaphroditism (MPH) is characterized by incomplete differentiation of male genitalia in the presence of testicular tissue. Enzymatic defects involving androgen synthesis or action are causes of MPH. We studied the molecular genetics of a large isolated inbred Turkish kindred with MPH due to either 5 alpha-reductase-2 (SRD5A2) or 17 beta-hydroxysteroid dehydrogenase-3 (17 beta HSD3) gene defects. Using single strand DNA conformational polymorphism analysis and DNA sequencing, a new mutation in exon 5 of SRD5A2 gene was detected in certain male pseudohermaphrodites from this kindred. This single base deletion (adenine) resulted in a frame shift at amino acid position 251 resulting in the addition of 23 amino acids at the carboxyl-terminal of this 254-amino acid isozyme. Transfection expression of the mutant isozyme in CV1 cells showed a complete loss of enzymatic activity in the conversion of [14C]testosterone to dihydrotestosterone, without a change in the messenger ribonucleic acid level compared to that of the wild-type isozyme. Analysis of the 17 beta HSD3 gene in other male pseudohermaphrodites from this kindred revealed a single point mutation (G-->A) at the boundary between intron 8 and exon 9, disrupting the splice acceptor site of exon 9. In this kindred, in addition to the identification of male pseudohermaphrodites with either a homozygous SRD5A2 or 17 beta HSD3 gene defect, other male pseudohermaphrodites were found to be genetically more complex: e.g. homozygous for the SRD5A2 defect and heterozygous for the 17 beta HSD3 defect, or homozygous for the 17 beta HSD3 defect and heterozygous for the SRD5A2 defect. Also, phenotypically normal carriers were identified with either one or both gene defects. Homozygous male pseudohermaphrodites with SRD5A2 or 17 beta HSD3 gene defects were phenotypically distinguishable by the presence of mild gynecomastia in the latter. Hormone data were consistent with the particular homozygous gene defect. In summary, we show 1) the novel existence of two gene defects, SRD5A2 and 17 beta HSD3, each causing MPH within a large isolated Turkish kindred; 2) that the two defects segregate independently and may be inherited from two different progenitors; and 3) analysis of a new mutation in exon 5 of SRD5A2 gene, supporting the functional importance of the carboxyl-terminal of 5 alpha-reductase-2 isozyme.

PMID: 9467575 [PubMed - indexed for MEDLINE]
1: J Clin Endocrinol Metab. 1996 May;81(5):1730-5. Related Articles, Links

5 alpha-reductase-2 gene mutations in the Dominican Republic.

Cai LQ, Zhu YS, Katz MD, Herrera C, Baez J, DeFillo-Ricart M, Shackleton CH, Imperato-McGinley J.

Department of Medicine, New York Hospital-Cornell University Medical College, New York 10021, USA.

Male pseudohermaphroditism due to 5 alpha-reductase deficiency was clinically and biochemically described in a large Dominican kindred of 23 families with 38 affected subjects in 1974. Recently, the 5 alpha-reductase-2 gene defect in the large Dominican kindred was found to be due to a single base substitution of thymidine (TGG) for cytosine (CGG) on exon 5 of the 5 alpha-reductase-2 gene, causing a tryptophan replacement of arginine at amino acid 246 (R246W) of the enzyme. In the present report, affected subjects from four additional Dominican families were studied to determine whether they carried the same 5 alpha-reductase-2 gene defect as the large kindred, suggesting a common ancestry for the gene defect within this small country. Using single strand conformational polymorphism and DNA sequencing, two other mutations of the 5 alpha-reductase-2 gene were found in affected subjects from two of the four families. A point mutation on exon 2 of the 5 alpha-reductase-2 gene, in which substitution of adenine (GAC) for guanine (GGC) caused an aspartic acid replacement of glycine at amino acid 115 (G115D), was demonstrated in one of these families, and a substitution of adenine (AGT) for guanine (GGT) on exon 3 causing a serine replacement for glycine at amino acid 183 (G183S) was detected in the other family. Affected subjects from the two remaining families demonstrated the same exon 5 mutation of the 5 alpha-reductase-2 gene as previously detected in the large Dominican kindred. The phenotypic and biochemical characteristics of the male pseudohermaphrodites were similar regardless of the genetic defect, except that one affected subject (C-VI-2) with the same exon 5 mutation as the large Dominican kindred had much more facial and body hair. Thus, the identification of multiple mutations in the 5 alpha-reductase-2 gene in male pseudohermaphrodites from the Dominican Republic demonstrates a lack of common ancestry, as had been previously postulated.

PMID: 8626825 [PubMed - indexed for MEDLINE]
1: J Endocrinol Invest. 1995 Mar;18(3):205-13. Related Articles, Links

Male pseudohermaphroditism due to primary 5 alpha-reductase deficiency: variation in gender identity reversal in seven Mexican patients from five different pedigrees.

Mendez JP, Ulloa-Aguirre A, Imperato-McGinley J, Brugmann A, Delfin M, Chavez B, Shackleton C, Kofman-Alfaro S, Perez-Palacios G.

Department of Reproductive Biology, Instituto Nacional de la Nutricion, Salvador Zubiran, Mexico, D.F., Mexico.

In the present study, we describe the clinical, endocrinological, psychosexual and biochemical features of 7 Mexican male pseudohermaphrodites with primary 5 alpha-reductase deficiency in whom heterogeneity in the pattern of gender identity change at puberty was observed. The patients belonged to 5 different pedigrees from diverse locations in Mexico. Six of them were admitted to the Hospital during or after puberty. The one prepubertal subject was the sibling of a previously studied patient. Basal serum gonadotropins were determined by double antibody radioimmunoassay. Basal and choriogonadotropin (CG)-stimulated concentrations of androstenedione (A), testosterone (T) and dihydrotestosterone (DHT) were determined by radioimmunoassay after extraction and separation by celite chromatography. Urinary aetiocholanolone, androsterone and C19 and C21 5 beta/5 alpha metabolite ratios were analyzed by capillary gas chromatography. Enzyme activity and androgen receptors were studied in fibroblasts cultured from genital skin. Psychological assessment was performed using the Bender-Gestalt Wechsler Adult Intelligence Scale, the Rorschach Ink Blot and the Thematic Apperception Tests. All 7 patients were unambiguously reared as females; three spontaneously changed their gender identity and role from female to male after puberty, another one changed during psychotherapy at the end of puberty. Two patients (one prepubertal and the other pubertal) have been under therapy during 1.5 years, but due to familial and social factors a female gender has prevailed. The remaining patient consulted at age 15 because of virilization; her female gender identity did not change after more than one year of treatment and due to the fact she was depressed and had suicidal tendencies, the penis and testes were removed.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 7615906 [PubMed - indexed for MEDLINE]
1: Eur Urol. 1994;25 Suppl 1:20-3. Related Articles, Links

5 alpha-reductase deficiency: human and animal models.

Imperato-McGinley J.

Department of Medicine, Cornell University Medical College, New York, NY 10021.

The syndrome of male pseudohermaphroditism secondary to 5 alpha-reductase deficiency is reviewed, as are hormonal evaluation and tissue studies documenting the enzyme deficiency. These studies reveal that the 5 alpha-metabolite dihydrotestosterone is essential for differentiation of the external genitalia and prostate. Studies of male rat fetuses treated with 5 alpha-reductase inhibitors during the critical period of sexual differentiation in utero reveal incomplete masculinization of the external genitalia and impaired prostate growth and development. Thus, conclusive evidence is provided for the hypothesis that 5 alpha-reductase activity and dihydrotestosterone formation are essential for normal differentiation of the male external genitalia and the prostate.

PMID: 8287893 [PubMed - indexed for MEDLINE]
1: J Clin Endocrinol Metab. 1979 Sep;49(3):391-5. Related Articles, Links

Male pseudohermaphroditism secondary to 17 beta-hydroxysteroid dehydrogenase deficiency: gender role change with puberty.

Imperato-McGinley J, Peterson RE, Stoller R, Goodwin WE.

A 31-yr-old male pseudohermaphrodite is reported with 17 beta-hydroxysteroid dehydrogenase deficiency. Laboratory data revealed a plasma testosterone of 228 ng/100 ml, a plasma androstenedione of 620 ng/100 ml, and an abnormal androstenedione to testosterone ratio. Plasma estradiol was 4.6 ng/100 ml and plasma estrone was 22 ng/100 ml. This subject was born in a hospital, incontrovertibly declared to be a female, and unambiguously raised as a girl by his parents for the first 17 yr of his life. At age 14 yr, he was able to change to a male gender role with ease. As an adult, he is a well adjusted, happily married man with a successful professional career. Surgical correction of bilateral cryptorchidism and hypospadias was carried out at age 14 yr. At age 30 yr, he developed a teratocarcinoma-seminoma of the right testis with retroperitoneal node metastases. After orchiectomy and retroperitoneal node dissection, he was placed on chemotherapy and is presently free of metastases.

PMID: 468973 [PubMed - indexed for MEDLINE]
1: N Engl J Med. 1979 May 31;300(22):1233-7. Related Articles, Links

Androgens and the evolution of male-gender identity among male pseudohermaphrodites with 5alpha-reductase deficiency.

Imperato-McGinley J, Peterson RE, Gautier T, Sturla E.

To determine the contribution of androgens to the formation of male-gender identity, we studied male pseudohermaphrodites who had decreased dihydrotestosterone production due to 5 alpha-reductase deficiency. These subjects were born with female-appearing external genitalia and were raised as girls. They have plasma testosterone levels in the high normal range, show an excellent response to testosterone and are unique models for evaluating the effect of testosterone, as compared with a female upbringing, in determining gender identity. Eighteen of 38 affected subjects were unambiguously raised as girls, yet during or after puberty, 17 of 18 changed to a male-gender identity and 16 of 18 to a male-gender role. Thus, exposure of the brain to normal levels of testosterone in utero, neonatally and at puberty appears to contribute substantially to the formation of male-gender identity. These subjects demonstrate that in the absence of sociocultural factors that could interrupt the natural sequence of events, the effect of testosterone predominates, over-riding the effect of rearing as girls.

PMID: 431680 [PubMed - indexed for MEDLINE]
1: Am J Med. 1977 Feb;62(2):170-91. Related Articles, Links

Male pseudohermaphroditism due to steroid 5-alpha-reductase deficiency.

Peterson RE, Imperato-McGinley J, Gautier T, Sturla E.

A new inherited form of male pseudohermaphroditism has been investigated in a pedigree of 24 families with 38 affected males. At birth, the affected males (46 XY) have a clitoral-like phallus, bifid scrotum and urogenital sinus. The testes are in the inguinal canals or labial-scrotal folds. The Wolffian structures are normally differentiated; there are no Mullerian structures. At puberty a muscular male habitus develops with growth of the phallus and scrotum, voice change and no gynecomastia. The subjects have erections, ejaculations and a libido directed towards females. They have decreased body hair, a scant to absent beard, no temporal hair line recession and a small prostate. Testicular biopsy reveals a normal testis. The mean plasma T levels in affected adults are significantly higher, and the mean plasma DHT levels are significantly lower when compared to those in normal subjects. The plasma T:DHT ratios range from 35 to 84 compared to 8 to 16 in normal subjects. After the administration of hCG, the T:DHT ratios in affected male children range from 74 to 162 compared to 3 to 26 in the control subjects. In affected adults, mean plasma LH and FSH levels are significantly higher than in normal subjects. In the affected subjects, the metabolic clearance rates of T and DHT are normal, but the conversion ratio of T to DHT is less than 1 per cent. The endogenous mean urinary E:A and E-OH:A-OH ratios, and the urinary E:A and E-OH:A-OH ratios after the infusion of radioactive T are significantly higher than in normal males. Inheritance is autosomal recessive with some sibling sisters showing the same biochemical defect, and obligate carrier parents showing an intermediate defect. These data support our thesis that the defect in these male pseudohermaphrodites is secondary to decreased steroid delta 4-5 alpha-reductase activity. The affected subjects provide a clinical model for delineating the roles of T and DHT in sexual differentiation and development. This entity also demonstrates an inherited disorder of steroid metabolism in which the basic enzyme deficiency resides in the target tissues.

PMID: 835597 [PubMed - indexed for MEDLINE]
Imperato-McGinley could not have a proof of her ideas, because we cannot study human brains without ethic problems, so some researchers studied androgen action in the non human primate brains, in rhesus fetuses....and their results confirm Imperato-McGinley ideas... Testosterone and not DHT is the important androgen in the basal systems of the brain, to masculinize gender identities, in non human primates, as in men.

1: Brain Res. 1992 Jan 20;570(1-2):68-74. Related Articles, Links

The interaction of testosterone with the brain of the orchidectomized primate fetus.

Michael RP, Zumpe D, Bonsall RW.

Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30322.

At certain times during gestation, the testes of the fetal macaque produce plasma levels of testosterone (T) that are similar to those of adults. It is thought that testosterone acts on the brain via estrogen and androgen receptors to organize the development of sexually dimorphic neural structures that underlie sex differences in behavior. To test the proposition that there are male-female differences in the occupation of steroid receptor binding sites during fetal development in the cynomolgus macaque, we have compared the uptake of [3H]T and its metabolites in: (1) 5 intact males (plasma T 571.2 +/- 215.5 ng/100 ml); (2) 5 intact females (33.8 +/- 25.2 ng/100 ml); (3) in 5 males orchidectomized in utero (14.6 +/- 5.7 ng/100 ml). About 1 week after fetal gonadectomy or sham-operation, all fetuses were given 500 microCi [3H]T s.c. and were then delivered 60 min later by Cesarean section. Brains were removed and dissected into blocks containing the hypothalamus and preoptic area, amygdala, hippocampus, and midbrain. Samples of cerebral and cerebellar cortex were also obtained. Purified nuclear pellets were prepared by centrifugation through 2 M sucrose and were extracted into ether and analyzed by high performance liquid chromatography. Hypothalamic nuclear concentrations of [3H]E2 in intact males (847 +/- 195 dpm per mg DNA) were significantly lower than those in sham-operated females (2147 +/- 542 dpm per mg DNA) (P less than 0.05), but those in orchidectomized males (2233 +/- 345 dpm per mg DNA) were similar to concentrations in females.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 1617431 [PubMed - indexed for MEDLINE]
1: Life Sci. 1992;50(6):409-17. Related Articles, Links

Immunohistochemical labeling of androgen receptors in the brain of rat and monkey.

Clancy AN, Bonsall RW, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30322.

Androgen receptor antibodies have recently been developed using fusion proteins containing fragments of human prostatic androgen receptor. We have used a polyclonal antibody raised in rabbits to label androgen receptors in brain sections from male and female rats and monkeys. Free-floating frozen sections were incubated in primary antibody, and processed by the peroxidase-avidin-biotin complex method using biotinylated anti-rabbit IgG. Nickel intensified diaminobenzidine was used as the chromagen, and neurons were labeled in the amygdala, hippocampus, bed nucleus of stria terminalis, septum, preoptic area, in several hypothalamic nuclei including the supraoptic and paraventricular nuclei, in several brain stem motor nuclei and in cerebral cortex. Staining was most intense in cell nuclei but also occurred in cytoplasm and in some neuronal processes. Labeling was more restricted in monkey than in rat brain. Omitting the primary antibody or pre-incubating the primary antibody with rat prostatic cytosol for control purposes demonstrated the specificity of staining.

PMID: 1734159 [PubMed - indexed for MEDLINE]
1: Neuroendocrinology. 1992 Jan;55(1):84-91. Related Articles, Links

Developmental changes in the uptake of testosterone by the primate brain.

Bonsall RW, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30306.

During the neonatal period in male macaques, the testis produces adult-like levels of plasma testosterone (T), but the function of this in development is not understood. To investigate the interaction of T with the neonatal brain, 4 male and 5 female cynomolgus monkeys were gonadectomized 2-5 days after birth, and were injected subcutaneously 3 days later with 500 microCi [3H]-testosterone ([3H]-T). 60 min later, brains and other tissue samples were removed. Purified nuclear pellets were prepared by centrifugation through 2 M sucrose, extracted into ether and analyzed by high-performance liquid chromatography. The aromatized metabolite, [3H]-estradiol [( 3H]-E2), was found only in the hypothalamus (HYP) and amygdala (AMG). In HYP, [3H]-E2 represented 55 +/- 3% of the radioactivity in males and 53 +/- 3% in females. In AMG, [3H]-E2 represented 40 +/- 9% of the radioactivity in males and 47 +/- 3% in females. Concentrations of unchanged [3H]-T were higher than those of [3H]-dihydrotestosterone [( 3H]-DHT). Both androgens were present in nuclear pellets from all 8 brain regions studied, and concentrations were significantly higher in females than in males (p less than 0.005). [3H]-T was also the main form of radioactivity in nuclear pellets from pituitary gland, adrenal gland, uterus and liver, but very high levels of [3H]-DHT were found in seminal vesicles, prostate and penis. Comparisons were made with previous results from orchidectomized fetuses at 122 days gestation and from fully adult male castrates, and the largest developmental changes occurred in the AMG where concentrations of [3H]-E2 were 20-fold higher in adults than in fetuses, and most of this increase took place after the neonatal stage. Nuclear concentrations of [3H]-T also increased markedly during development in most brain regions except the cerebellar cortex where they declined.

PMID: 1608511 [PubMed - indexed for MEDLINE]
1: Neuroendocrinology. 1990 Apr;51(4):474-80. Related Articles, Links

Comparisons of the nuclear uptake of [3H]-testosterone and its metabolites by the brains of male and female macaque fetuses at 122 days of gestation.

Bonsall RW, Zumpe D, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, Ga.

Testosterone secreted by the testis of the macaque fetus is thought to influence certain aspects of the brain's subsequent development which may be responsible for the ontogeny of sexually dimorphic patterns of behavior. To compare the interactions between testosterone and the receptors for androgens and estrogens in brain cell nuclei in the two sexes, 7 intact female fetuses and 5 intact male fetuses were injected in utero at about 120 days of gestation with [3H]-testosterone (250 microCi i.v. or 500 microCi s.c.). One hour later, fetuses were delivered by cesarean section, and samples of brain and peripheral tissues were homogenized and separated into purified nuclear and supernatant fractions. Fractions were analyzed by high performance liquid chromatography to measure levels of [3H]-testosterone and its metabolites. Concentrations of radioactivity extracted from cell nuclei were significantly higher in the hypothalamus-preoptic area than in other brain areas (p less than 0.001); [3H]-estradiol represented 65.0 +/- 5.7% of this radioactivity and nuclear concentrations of this metabolite were 73% lower in males than in females (p less than 0.001). Nuclear concentrations of [3H]-testosterone in the pituitary gland (68.9 +/- 8.8% of extracted radioactivity) were 48% lower in males than in females (p less than 0.001). There was no evidence of a sex difference in the tissue uptake of radioactive steroids from blood, but in males, levels of endogenous plasma testosterone (599.8 +/- 208.2 ng/100 ml) were significantly higher than in females (37.7 +/- 28.5 ng/100 ml; p less than 0.01), and the specific activity of [3H]-testosterone in blood was consequently lower in males than in females.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 2111895 [PubMed - indexed for MEDLINE]
1: Brain Res. 1989 Nov 13;502(1):11-20. Related Articles, Links

Sites in the male primate brain at which testosterone acts as an androgen.

Michael RP, Rees HD, Bonsall RW.

Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30322.

Quantitative autoradiographic analysis was used to identify regions in the brain of the male primate where androgen binding sites may be involved in the actions of testosterone. Three days after castration, adult male rhesus monkeys received a subcutaneous injection of either dihydrotestosterone propionate (DHTP, 20 mg, n = 6), testosterone propionate (TP, 100 mg, n = 2), or oil vehicle (control males, n = 4). Three hours later, 5 mCi [3H]testosterone was administered as an i.v. bolus. At 60 min, brains were rapidly removed and the left halves were used for autoradiography. In control males, highest percentages of labeled neurons (20-84% using a rigorous Poisson criterion) were observed in the ventromedial, arcuate and premammillary nuclei (n.) of the hypothalamus, medial preoptic n., bed n. of stria terminalis, intercalated mammillary n., lateral septal n. and the medial, cortical and accessory basal n. of the amygdala. Pretreatment with DHTP eliminated labeling in androgen target tissues of the genital tract, and reduced the percentages of labeled neurons to 4-22% of control values in the arcuate, lateral septal, premammillary and intercalated mammillary n., indicating that in these regions testosterone acted predominantly at androgen binding sites. However, in the medial preoptic n., the ventromedial hypothalamic n. and the accessory basal amygdaloid n., DHTP pretreatment resulted in much less blocking which, together with other data, suggested that in these sites, testosterone's actions involved aromatization and interaction with estrogen-binding sites.

PMID: 2819450 [PubMed - indexed for MEDLINE]
1: J Steroid Biochem. 1989 Sep;33(3):405-11. Related Articles, Links

Pretreatments with 5 alpha-dihydrotestosterone and the uptake of testosterone by cell nuclei in the brains of male rhesus monkeys.

Bonsall RW, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia 30322.

An in vivo competition method was used in adult male rhesus monkeys to determine if testosterone binds to high affinity binding agents, notably androgen receptors, in brain cell nuclei. Castrated males received 5 alpha-dihydrotestosterone propionate (DHTP, 20 mg, N = 6), testosterone propionate (TP, 100 mg, N = 3) or oil vehicle (controls, N = 6) followed 3 h later by 5 mCi [3H]testosterone [( 3H]T) as an intravenous bolus. Brain and peripheral tissue samples were removed after 60 min, homogenized and separated into supernatant and purified nuclear fractions. Radioactive metabolites of [3H]T [( 3H]estradiol, [3H]DHT) and unchanged [3H]T were identified by high performance liquid chromatography (HPLC). Androgen pretreatments reduced the nuclear uptake of [3H]T by 67-98% in hypothalamus (HYP), preoptic area (POA) and pituitary gland (PIT). This blockade was presumed to be due to prior occupation of nuclear androgen receptors by unlabeled androgens because pretreatments had no effects on levels of [3H]T in supernatants. Since [3H]T was the major radioactive androgen present in brain cell nuclei, results strongly suggested that the principal nuclear androgen receptor ligand in HYP, POA and PIT was unchanged [3H]T rather than [3H]DHT as occurs in the genital tract. In the amygdala the situation was quite different. Here, nuclear concentrations of [3H]T were reduced by 67% following TP pretreatment but were not changed following DHTP pretreatment, indicating a different uptake mechanism in this region that could have particular relevance for testosterone's central actions on behavior.

PMID: 2779232 [PubMed - indexed for MEDLINE]
1: J Steroid Biochem. 1989 Apr;32(4):599-608. Related Articles, Links

Identification of radioactivity in cell nuclei from brain, pituitary gland and genital tract of male rhesus monkeys after the administration of [3H]testosterone.

Bonsall RW, Rees HD, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30322.

Enzymes are present in the primate brain that convert testosterone into 17 beta-hydroxy-5 alpha-androstan-3-one (dihydrotestosterone), estradiol-17 beta and 4-androstene-3,17-dione. To identify the metabolites of testosterone that accumulate in cell nuclei obtained from different regions of the brain, 9 adult castrated male rhesus monkeys were injected with 5 mCi [3H]testosterone as an intravenous bolus. After 1 h, brains were rapidly removed and the left halves were used for autoradiography while the right halves were dissected to provide 14 samples. Radioactive metabolites in cell nuclei were identified by high-performance liquid chromatography (HPLC) and by repeated recrystallization. In autoradiograms of brain, most of the labeled neurons were in the hypothalamus, preoptic area and amygdala. These three regions also had the highest levels of radioactivity. The major form of this radioactivity was [3H]estradiol-17 beta (Type I tissues) and the major radioactive androgen present was [3H]testosterone. In all other brain regions and pituitary gland, the major form of radioactivity was unchanged [3H]testosterone (Type II tissues). In genital tract structures, [3H]dihydrotestosterone predominated (Type III tissues). These results suggested that, in contrast to its actions on genital tract structures, testosterone acts on neuronal nuclei mainly in unmetabolized form or after conversion to estradiol-17 beta.

PMID: 2724964 [PubMed - indexed for MEDLINE]
1: Endocrinology. 1989 Mar;124(3):1319-26. Related Articles, Links

The uptake of [3H]testosterone and its metabolites by the brain and pituitary gland of the fetal macaque.

Michael RP, Bonsall RW, Rees HD.

Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia 30322.

Testosterone is secreted by the fetal testis during gestation, and this is thought to influence certain aspects of the brain's subsequent development. To study this action at the neuronal level, nine macaque fetuses were injected with 250 microCi [3H]testosterone via the umbilical vein at about 120 days gestation. After 60 min, samples of brain and peripheral tissue were studied by autoradiography or HPLC. Purified nuclear pellets were prepared, and radioactivity in ether extracts was fractionated by HPLC and identified by coelution with internal standard steroids. Concentrations of radioactivity were significantly higher (P less than 0.05) in the hypothalamus-preoptic area than in amygdala, hippocampus, midbrain, and cerebral and cerebellar cortexes, and most of the radioactivity (75%) in the hypothalamus-preoptic area coeluted with 17 beta-estradiol. Radioactivity coeluting with 17 beta-estradiol was also detected in nuclear fractions from amygdala (44%). In contrast, 80% of the radioactivity extracted from pituitary gland nuclei coeluted with testosterone. Most of the neurons labeled in autoradiograms were located in the hypothalamus and preoptic area, fewer were found in the amygdala, and labeling in the frontal or motor cortex did not exceed chance levels. Results suggested that aromatization and, consequently, estrogen receptors play a role in the effects of testosterone on the hypothalamus and amygdala of the primate fetus at this stage of development.

PMID: 2917514 [PubMed - indexed for MEDLINE]
1: Cell Tissue Res. 1988 Oct;254(1):139-46. Related Articles, Links

Localization and identification of nuclear radioactivity in the pituitary gland and genital tract after administering 3H-testosterone, 3H-dihydrotestosterone, or 3H-estradiol to male rhesus monkeys.

Rees HD, Bonsall RW, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, Georgia 30322.

Target cells for testosterone, dihydrotestosterone, and estradiol in the pituitary gland and genital tract of the male primate were localized by thaw-mount autoradiography, and high performance liquid chromatography was used to identify the metabolites of these steroids in cell nuclei. Castrated rhesus monkeys were injected with 3H-testosterone, 3H-dihydrotestosterone, or 3H-estradiol and killed 60 min later. In the anterior pituitary gland, fewer cells were labeled and less radioactivity was taken up by cell nuclei following the administration of either 3H-testosterone (4% of pars distalis cells and 5 dpm/micrograms DNA) or 3H-dihydrotestosterone (5% of cells and 13 dpm/micrograms DNA) than following the administration of 3H-estradiol (43% of cells and 214 dpm/micrograms DNA). Most of the radioactivity in nuclei was in the form of the unmetabolized parent compound (78-94%). In prostate, seminal vesicles, and penis, 3H-dihydrotestosterone was the predominant form of nuclear radioactivity following both 3H-testosterone (67-90%) and 3H-dihydrostestosterone (94-97%) administration, and both androgens labeled epithelial and smooth muscle cells. In contrast, 3H-estradiol was taken up in unchanged form, by cell nuclei of the genital tract and it labeled connective tissue fibroblasts, but not epithelial cells. Thus, the distributions of target cells for androgens and estrogens were clearly different in all these tissues, and the uptake of testosterone resembled that of its androgenic rather than that of its estrogenic metabolite.

PMID: 3197077 [PubMed - indexed for MEDLINE]
1: Brain Res. 1988 Jun 14;452(1-2):28-38. Related Articles, Links

Estrogen binding and the actions of testosterone in the brain of the male rhesus monkey.

Rees HD, Bonsall RW, Michael RP.

Department of Psychiatry, Emory University School of Medicine, Atlanta, GA 30322.

Autoradiography and high performance liquid chromatography (HPLC) were used to determine where metabolites of testosterone interact with estrogen binding sites in the brain of the male primate. Three days after castration, animals received a subcutaneous injection of either estradiol benzoate (EB, 200 micrograms/kg, n = 4) or oil vehicle (controls, n = 4). Three hours later, 5 mCi [3H]testosterone was administered as an intravenous bolus. At 60 min, brains were rapidly removed, left halves were used for autoradiography and right halves were dissected into 14 samples for HPLC of nuclear and supernatant fractions. In control males, labeled neurons were observed in preoptic area, hypothalamus and amygdala. In EB-pretreated males, the number of labeled neurons was reduced by 35% in the anterior hypothalamus and ventromedial nucleus, and by 65% in the cortical and accessory basal amygdaloid nuclei, but was not significantly reduced in other brain regions. In hypothalamus, preoptic area and amygdala, EB-pretreatment reduced nuclear concentrations of [3H]estradiol to 37-55% of control levels, but reduced neither the nuclear concentrations of [3H]testosterone nor the supernatant concentrations of [3H]estradiol and [3H]testosterone. The data suggest that the actions of testosterone in regions such as the arcuate nucleus and lateral septal nucleus primarily involve unchanged testosterone or dihydrotestosterone, while in regions such as the amygdala, aromatization and interaction with estrogen receptors is involved also.

PMID: 3401735 [PubMed - indexed for MEDLINE]
1: Neuroendocrinology. 1987 Dec;46(6):511-21. Related Articles, Links

Sites at which testosterone may act as an estrogen in the brain of the male primate.

Michael RP, Bonsall RW, Rees HD.

Department of Psychiatry, Emory University School of Medicine, Atlanta, Ga.

Testosterone is converted to estradiol in specific regions of the primate brain and accumulates as such in the nuclei of cells in hypothalamus, preoptic area, and amygdala. To locate more precisely those neurons in which nuclear estrogen receptors were occupied by estrogenic metabolites of testosterone, we injected 8 castrated male rhesus monkeys with [3H]-estradiol. Four were injected with oil for control purposes, and 4 were pretreated for 3 days with 2 mg/day testosterone propionate. This dose raised plasma testosterone levels into the high physiological range for intact males. After 60 min, brains were rapidly removed, the levels of [3H]-estradiol in nuclei were measured in the right halves of the brains by high-performance liquid chromatography, and labeled neurons were located in the left halves by autoradiography. Compared with the 4 control animals, nuclear levels of [3H]-estradiol in testosterone-treated males were reduced by 77% in the hypothalamus (p less than 0.001), by 93% in the preoptic area (p less than 0.001), and by 90% in the amygdala (p less than 0.05). In autoradiograms from testosterone-treated males, the labeling of neurons was reduced by 72-96% in most of the regions in which the control males showed high percentages of labeled cells. However, there were only small reductions in the number of labeled neurons in lateral septum (by 31%) and arcuate nucleus (by 23%). These two regions, therefore, contained estrogen receptors that were not blocked by pretreatment with testosterone. The simplest explanation for these results is that estrogenic metabolites of testosterone prevented the uptake of [3H]-estradiol by prior occupation of estrogen receptor sites. The rather precise neuroanatomical localization of the effects pointed to the existence of two populations of estrogen target neurons in the primate brain depending on the presence or absence of local aromatase activity.

PMID: 3122067 [PubMed - indexed for MEDLINE]
1: J Steroid Biochem. 1988 Apr;29(4):429-34. Related Articles, Links

Testosterone 5 alpha-reductase activity in neural tissue of fetal rhesus macaques.

Resko JA, Connolly PB, Roselli CE.

Department of Physiology, Oregon Health Sciences University, Portland 97201.

After development of a 5 alpha-reductase activity (5 alpha-RA) assay based on the capacity of microsomes to convert [3H]testosterone (T) to [3H]dihydrotestosterone (DHT), we analyzed 5 alpha-RA in neural tissues of fetal rhesus macaques at 50, 80 and 150 days of gestation. This method allowed us to collect kinetic data on the properties of the 5 alpha-reductase resident in fetal brain at 150 days of gestation. The Km and Vmax calculated from these data were 4.32 microM and 22.6 protein-1.h-1, respectively. Analyses of 5 alpha-RA in microsomes from the hypothalamic-preoptic area-amygdala (HPA) at dilutions of 1/25 and 1/50 indicated higher enzyme activity with increasing dilution of the microsomes. Measurement of 5 alpha-RA using concentrations of [3H]T which saturated the enzyme in diencephalon (DIEN), brain stem (B.STEM), temporal (TCTX) and frontal cortex (FCTX) of six 50-day old fetuses (3 males and 3 females) revealed no obvious sex differences in 5 alpha-RA, however, a significant difference (P less than 0.05) between tissues was noted. The DIEN and B.STEM contained significantly (P less than 0.05) higher levels 5 alpha-RA than the FCTX while the TCTX contained an intermediate level of activity. Significant increases in 5 alpha-RA were observed in FCTX and TCTX with time of gestation (50, 80 and 150 days). Other tissues, including amygdala, hippocampus, cerebellum, tegmentum and septum also change with fetal age. These data demonstrate the existence of 5 alpha-reductase in the fetal monkey brain. Significant changes in cortical 5 alpha-RA suggest some role for 5 alpha-reductase in development.

PMID: 3374132 [PubMed - indexed for MEDLINE]
1: Neuroendocrinology. 1990 Jul;52(1):94-8. Related Articles, Links

Aromatase, 5-alpha-reductase, and androgen receptor levels in the fetal monkey brain during early development.

Sholl SA, Kim KL.

Wisconsin Regional Primate Research Center, University of Wisconsin, Madison.

Aromatase, 5 alpha-reductase and cytosolic androgen receptor levels were measured in the medial basal hypothalamus (MHB), amygdala (AMG), cerebellum and cerebral cortex of male and female fetal rhesus monkeys on day 70 of gestation. Higher aromatase activities were noted in the MBH and AMG of male than female fetuses. In contrast, no sex differences were found for 5 alpha-reductase and androgen receptor levels. These data suggest that at this early stage of development, differentiation of the MBH and AMG of the male fetus may be more susceptible to androgen modification, by way of aromatization to estrogens, than corresponding areas in the female fetus. Moreover, based upon a comparison of the current data to that published previously for later stages of development, it is suggested that the sex differences in aromatase activity are not the result of androgen stimulation.

PMID: 2118611 [PubMed - indexed for MEDLINE]