Two subtypes of androgen and progestogen receptors in fish testes

Two subtypes (alpha and beta) of androgen (AR) and progestogen receptors (PR) are present in the testis of Japanese eel (Anguilla japonica). Amino acid homology of the open reading frames between alpha and beta in AR or PR is approximately 40%, but the DNA- and ligand-binding domains show high homology between subtypes. Judging from these structures, alpha and beta are not isoforms derived from translational initiation at two in-phase ATG codons, alternative splicing, or tetraploidy. In transient transfection assays using a reporter construct containing a steroid-responsive promoter, each subtype showed its corresponding hormone-dependent transactivation. The ligand affinity for transactivation between AR and PR subtypes was similar for physiological ligands. Tissue distribution of both subtype mRNAs was different. Protein interaction between subtypes was demonstrated in vitro by GST pull-down assays. These results clearly indicate that two functional subtypes of AR and PR exist in eel. These findings will advance our understanding of the mechanisms underlying sex steroid signaling.     

Increased peripheral aromatase activity in prepubertal children with partial androgen insensitivity syndrome

It has been suggested that rate of estrogen formation was higher in patients with androgen insensitivity syndrome (AIS). This work was designed to find out if peripheral aromatase activity could be related to a defect in androgen action in prepubertal children with male pseudohermaphroditism. Fibroblast estrogen production was assayed by a highly specific enzymatic determination. Foreskin fibroblast strains were raised from 17 children with partial androgen insensitivity (PAIS) as defined by dihydrotestosterone binding activity in cells. Results are expressed as pmol estrogens/mg proteins synthetized/day when cultured fibroblasts are incubated with D4-androstenedione. In normal prepubertal boys (n = 19), aromatase activity ranged between 5 and 10 pmol estrogens/mg proteins/day, while in postpubertal boys it varied between 15 and 34 pmol estrogens/mg proteins/day. In prepubertal boys with PAIS (n = 17) aromatase activity is highly elevated: 19.4 +/- 8.4 pmol/mg proteins/day. These results show that (a) peripheral aromatase activity is low before puberty and (b) fibroblast estrogen synthesis is significantly (p less than 0.001) increased in prepubertal children with PAIS. Our data suggest that low utilization of androgens by target cells stimulates the production of estrogen. Peripheral aromatase activity can thus be considered as a 'marker' of androgen insensitivity in prepubertal children with male pseudohermaphroditism.     

Detection of aromatase, androgen, and estrogen receptors in bank vole spermatozoa

Spermatozoa are highly specialized cells which transport a single-copy haploid genome to the site of fertilization. Before this, spermatozoa undergo a series of biochemical and functional modifications. In recent years, the crucial role of androgens and estrogens in proper germ cell differentiation during spermatogenesis has been demonstrated. However, their implication in the biology of mature male gametes is still to be defined. Our study provides evidence for the first time that aromatase, the androgen receptor (AR), as well as the estrogen receptors α and β (ERα and ERβ), are present in bank vole spermatozoa. We demonstrated the region-specific localization of these proteins in bank vole spermatozoa using confocal microscopy. Immunoreactive aromatase was observed in the proximal head region and in both the proximal and distal tail regions, whereas steroid hormone receptors were found only in the proximal region of the sperm head. Protein expression in sperm lysates was detected by Western blot analysis. Immunohistochemical results were analyzed quantitatively. Our results show that bank vole spermatozoa are both a source of estrogens and a target for steroid hormone action. Moreover, the presence of aromatase and steroid hormone receptors in the bank vole spermatozoa indicates a potential function of these proteins during capacitation and/or the acrosome reaction.     

Expression of aromatase,androgen and estrogen receptors in peripheral target tissues in diabetes

Our previous studies have shown that diabetes in the male streptozotocin (STZ)-induced diabetic rat is characterized by a decrease in circulating testosterone and concomitant increase in estradiol levels. Interestingly, this increase in estradiol levels persists even after castration, suggesting extra-testicular origins of estradiol in diabetes. The aim of the present study was to examine whether other target organs of diabetes may be sources of estradiol. The study was performed in male Sprague–Dawley non-diabetic (ND), STZ-induced diabetic (D) and STZ-induced diabetic castrated (Dcas) rats (n = 8–9/group). 14 weeks of diabetes was associated with decreased testicular (ND, 26.3 ± 4.19; D, 18.4 ± 1.54; P < 0.05), but increased renal (ND, 1.83 ± 0.92; D, 7.85 ± 1.38; P < 0.05) and ocular (D, 23.4 ± 3.66; D, 87.1 ± 28.1; P < 0.05) aromatase activity. This increase in renal (Dcas, 6.30 ± 1.25) and ocular (Dcas, 62.7 ± 11.9) aromatase activity persisted after castration. The diabetic kidney also had increased levels of tissue estrogen (ND, 0.31 ± 0.01; D, 0.51 ± 0.11; Dcas, 0.45 ± 0.08) as well as estrogen receptor alpha protein expression (ND, 0.63 ± 0.09; D, 1.62 ± 0.28; Dcas, 1.38 ± 0.20). These data suggest that in male STZ-induced diabetic rats, tissues other than the testis may become sources of estradiol. In particular, the diabetic kidney appears to produce estradiol following castration, a state that is associated with a high degree or renal injury. Overall, our data provides evidence for the extra-testicular source of estradiol that in males, through an intracrine mechanism, may contribute to the development and/or progression of end-organ damage associated with diabetes.     

Seasonal expression of androgen receptors, estrogen receptors, and aromatase in the canary brain in relation to circulating androgens and estrogens

Songbirds have a complex neural network for learning and production of song, namely the neural song system. Several nuclei of the song system contain androgen receptors (AR), and the neostriatal nucleus HVc also contains alpha type estrogen receptors (ER). Many songbird species show seasonal changes in both song and the neural song system that are correlated with seasonal variations in the circulating levels of gonadal steroids. However, there is increasing evidence that the sensitivity of the song system to gonadal steroids also changes seasonally. This could involve changes in the expression and activity of steroid receptors and steroid-metabolizing enzymes, such as the estrogen-synthesizing enzyme aromatase (AROM). The seasonal regulation of brain AR, ER, and AROM has not been studied before in the same individual songbirds. In this work, we compared plasma levels of androgens and estrogens, the expression level of AR-, ER-, and AROM-mRNA in the telencephalon, and brain AROM activity in male canaries between autumn (November) and spring (April) periods of high singing activity. Plasma levels of androgens and estrogens were higher in April than in November. The expression level of ER in HVc was higher in November than in April. In contrast, the expression level of AROM in the caudomedial neostriatum was higher in April than in November. However, we found no seasonal differences in the level of expression of AR and the volume of HVc as delimited by AR expression. Thus, AR expression in HVc was not correlated with circulating androgen levels. This study shows that both steroid-dependent and -independent seasonal factors regulate the action of gonadal hormones on the song system. In addition, we report a new site of AROM expression in the songbird brain, the nucleus interfacialis.     

Presence of positive feedback in males with Klinefelter's syndrome

This study examined the effect of 17 beta-estradiol (E2) on basal and luteinizing hormone (LH)-releasing hormone (LHRH)-stimulated gonadotropin secretion in 9 patients with Klinefelter's syndrome. Intramuscular injection of E2 (10 micrograms/kg/day during 5 days) induced a rapid decrease in follicle-stimulating hormone (FSH) and LH levels. The maximum suppression was observed on day 7 (D7) for FSH [median 9.7 mIU/ml (range 4.6-37.8) vs. 21.7 mIU/ml (range 12.2-56.9)] and on D2 for LH [median 13.6 mIU/ml (range 6.8-25.2) vs. 21.2 mIU/ml (range 13-54.7)]. E2 concentrations rose and reached their peak values on D3 [median 723 pmol/l (range 517-1,247.8) vs. 110.1 pmol/l (range 68.6-227.5) on D0]. These changes were followed by a subsequent rise in LH on D4 [36.7 mIU/ml (range 19.4-77.7)]. LH response to LHRH was higher during E2 treatment: median value of absolute peaks: 156.3 mIU/ml (range 56.7-188.6) on D4 vs. 64 mIU/ml (range 38.9-131) on DO. These results demonstrate the presence of a positive feedback in patients with Klinefelter's syndrome.     

Crimino-biologic study of patients with the XYY syndrome and Klinefelter's syndrome

Summary 12 psychopathic patients with chromosome aberrations found among 480 individuals in two institutions for criminal psychopaths in Denmark have been crimino-biologically investigated. 5 of these individuals have Klinefelter's syndrome, 5 are of the XYY karyotype, 1 is 46,XY/47,XY ?Xq- mosaic, and the remaining one is 46, ?Xp-Y.The mean age at first offence is 18.5 years; 83% are recidivists with the mean number of sentences being 7.0. The criminal acts of 5 patients with the XYY syndrome consist mainly of petty thieving, indecency and arson. The criminal offences of 5 patients with Klinefelter's syndrome is mainly petty thieving, sexual offences and less violent crimes. The relationships between the individual criminal life curve, age at first offence, number of sentences, criminality among siblings, milieu factors, intelligence, and psychiatric diagnosis are discussed.Psychoinfantile personality is pronounced in 5 patients with Klinefelter's syndrome. Schizoid personality was remarkable in 3 patients with the XYY syndrome.

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Zusammenfassung 12 psychopathische Patienten mit Chromosomenaberrationen, die unter 480 Insassen von zwei Anstalten für kriminelle Psychopathen in Dänemark gefunden wurden, wurden kriminalbiologisch untersucht: 5 von ihnen hatten das Klinefelter-Syndrom, 5 zeigten den XYY-Karyotyp, 1 war 46, XY/47,XY,?Xq-Mosaik, der letzte war 46, ?Xp-Y.Das Durchschnittsalter bei dem ersten Vergehen war 18,5 Jahre; 83% wurden rückfällig; die durchschnittliche Zahl der Verurteilungen betrug 7,0. Die Vergehen der 5 Personen mit XYY-Syndrom bestanden vor allem aus geringfügigen Diebereien, Sittlichkeitsvergehen und Brandstiftung. Die Vergehen der 5 Patienten mit Klinefelter-Syndrom setzten sich vor allem zusammen aus geringfügigen Diebereien, sexuellen Vergehen und weniger gewaltsamen Vergehen. Die Beziehungen zwischen den individuellen Lebensläufen bezüglich der Kriminalität, dem Alter beim ersten Vergehen, der Zahl der Verurteilungen, der Kriminalität unter Geschwistern, den Milieufaktoren, der Intelligenz und der psychiatrischen Diagnose werden diskutiert. Bei 5 Patienten mit Klinefelter-Syndrom finden sich deutliche Zeichen einer psychoinfantilen Persönlichkeit. 3 Patienten mit XYY-Syndrom zeigten deutliche schizoide Züge.

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The author dedicates this paper to emeritus Prof. Dr. S. Yoshimasu on his 70th birthday.

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Stipendiat of the Alexander von Humboldt-Stiftung.     

Low aromatase activity and gene expression in human fetal testes

Because of previous indications that estradiol (E2) plays a role in the regulation of testicular testosterone (T) production in some species, the production of E2 and aromatase gene expression in human fetal testes were investigated. Testicular minces from 14 fetuses (fetal age 15-23 weeks) were incubated with and without 200 ng/ml highly purified hCG, and the production of E2 and T was measured by RIA. Basal T production was high at 15-18 weeks of gestation and decreased thereafter. Estradiol production was low in all testes. Aromatase mRNA (P-450 arom messenger ribonucleic acid) was not detectable in fetal testicular tissues when studied by Northern and dot blot techniques. Placenta and fetal liver expressed aromatase mRNA, but fetal ovary contained only miniscule amounts. HCG significantly stimulated the production of both T and E2 in the testes of older fetuses (19-23 weeks), but the testicular E2 production of the youngest fetuses (15-18 weeks) did not increase significantly after hCG stimulation. These results indicate that aromatase activity and gene expression are very low in human fetal testes. These findings suggest that E2 may not play a major role in testicular T production in the human fetus.     

Immunolocalization and activity of aromatase in the bank vole testes.

A direct approach to identify the cellular source of P450 aromatase in the bank vole testes (seasonally breeding rodents) is the use of immunohistochemistry with a specific antibody that recognizes this enzyme. To confirm the presence of functional aromatase, its activity was measured in microsomal preparations of whole testes and of seminiferous tubules by means of biochemical assay with tritiated androstenedione. The assay was validated using increasing concentrations of both microsomal preparations. Immunoreactive aromatase was found in Leydig cells, Sertoli cells, and germ cells, especially in spermatocytes and spermatids. The aromatase activity was present in microsomal fractions of whole testis and seminiferous tubules. The immunolocalization of P450 aromatase and aromatase activity have been found as photoperiod-dependent.