Expression of 3ß-HSD1 and P450 Aromatase enzymes during mouse gonad differentiation.

In sheep embryos, steroidogenic activity has been reported as taking place during the period of sexual differentiation. In the case of mouse embryos, the sporadic detection or absence of steroidogenic enzymes suggests that the ovary is inactive. The purpose of this work was to establish if mouse undifferentiated gonads express steroidogenic enzymes in a similar way as in sheep embryos. To know this, we analyzed the mRNA expression pattern of 3ß-Hsd1 and P450arom as well as protein expression pattern of 3ß-HSD1 and Testosterone in normal undifferentiated and differentiated gonads from both male and female mice embryo. Our data indicate that there is expression of 3ß-Hsd1 in XX gonads during gonad differentiation period. Nevertheless the Testosterone which would indicate steroidogenic activity is not produced. Besides, the absence of P450arom indicates that the production of Estradiol as observed in the ovaries of sheep does not occur. The detection of 3ß-Hsd1 in the early stages of ovarian development, as well as the absence of Testosterone suggests that XX gonads are not steroidogenic and that 3ß-Hsd1 enzyme may play a different role than in the steroidogenesis process.

Alterations of folliculogenesis in women with polycystic ovary syndrome.

The objective of the present study was to examine some factors involved in follicular development of women with polycystic ovary syndrome (PCOS). Women with PCOS showed increased levels of serum luteinizing hormone (LH) but decreased follicular production of progesterone and estradiol by pre-ovulatory follicles. The mRNA expression corresponding to steroidogenic acute regulatory protein (StAR), and 20alpha-hydroxysteroid dehydrogenase (20α-HSD) was increased, while that corresponding to cytochrome P450 aromatase (P450arom) was decreased in PCOS follicles as compared to controls. No changes in the mRNA expression for 3beta-hydroxysteroid dehydrogenase 2 (3ß-HSD2), cytochrome P450 side-chain cleavage (P450scc), cytochrome P450 17 alpha hydroxylase/lyase (P450c17), cyclooxygenase 2 (COX2), and transcription factors (GATA-4 and GATA-6) were found. We conclude that despite the hyper-luteinized environment of PCOS follicles, these follicles produce lower levels of progesterone and estradiol, and that this is characterized by increased degradation of progesterone and decreased estradiol synthesis. Our data demonstrate that the synthesis of prostaglandin F2α (PGF2α) may be affected in PCOS-follicles and that the transcription factors GATA-4 and GATA-6 are present in PCOS-follicles but they are not involved in the abnormal transcription observed in the steroidogenic enzymes.

Mild calorie restriction does not affect testosterone levels and testicular gene expression in mutant mice.

The hypothalamic-pituitary-gonadal (HPG) axis and the somatotropic axis are influenced by nutritional factors. Calorie restriction (CR) extends lifespan but suppresses both the HPG and the somatotropic axes. Since most CR studies use a fairly severe (40%-60%) reduction of calorie intake, we hypothesized that a milder CR (20%) might not be deleterious to reproduction in male mice. To test this hypothesis, we evaluated the effects of 20% CR on testicular testosterone content and on testicular expression of genes that are relevant to testicular function and reproductive competence, including insulin-like growth factor-I, cytochrome P450 aromatase (Cyp19a1), androgen receptor, luteinizing hormone receptor, follicle-stimulating hormone receptor, cytochrome P450c17 and 3-beta-hydroxysteroid dehydrogenase/isomerase. To relate CR effects to the activity of the somatotropic axis, we have used growth hormone-resistant GHR knockout mice as well as transgenic mice overexpressing GH. Mild CR did not affect testosterone levels in testis homogenates and had little effect on expression of the examined genes in the reproductive organs. Altered activity of the GH/insulin-like growth factor-1 axis had a major impact on the parameters analyzed. The results also suggest that expression of several key genes involved in the control of testicular function is preserved under conditions of mild CR and encourage speculation that mild regimens of CR can produce longevity benefits without impairing reproduction.

Testosterone metabolism in vitro by male sexual accessory glands from normal and autoimmunized rabbits.

In vitro metabolism of (3H)-testosterone from male accessory gland homogenates from autoimmunized and normal rabbits was studied at different times of incubation. Results indicated that 5 alpha - androstane-3 alpha, 17 beta-diol was the main metabolite formed in both cases, though the presence of the 3 beta-isomer cannot be excluded. On autoimmunized rabbits with small histological alteration, transformation of the precursor (3H)-testosterone was significantly greater (40 min: P less than 0.01; 60 min: P less than 0.05). This led to a higher yield of 5 alpha-androstane-3 alpha, 17 beta-diol at both incubation times, being significant only at 40 min (P less than 0.02). The 4-androstene-3,17-dione also increased as compared with the normal group. In autoimmunized rabbits with a greater histological alteration, the bioconversion of (3H)-testosterone decreased for both incubation times, being significant only for the 40 min (P less than 0.05). A decreased interconversion to 4-androstene-3,17-dione was also observed, being significant only for 40 min (P less than 0.05). These results suggest that in an early stage of autoimmunization there might be a transient stimulation of enzyme activities in the sexual accessory glands. In another moment of the phenomena a more severe histological lesion with infiltration of male accessory glands was present. At the same time, decrease in the enzymatic activities could be noticed.