Expression and phylogeny of candidate genes for sex differentiation in a primitive fish species, the Siberian sturgeon, Acipenser baerii.

The molecular mechanisms underlying testis differentiation in basal actinopterygian fish remains poorly understood. The sex differentiation period was investigated in the Siberian sturgeon, Acipenser baerii, by expression profiling of Sertoli cell transcription factors (dmrt1, sox9) that control testis differentiation in vertebrates; Leydig cell factors (cyp17a1, star) affecting androgen production; the androgen receptor (ar); a growth factor controlling testis development (igf1); and a gene coding for a gonadotropin hormone (lh). Two genes were characterised for the first time in the Siberian sturgeon (dmrt1, cyp17a1), while the others came from public databases. Sturgeon gonad development is very slow, with a late sexual differentiation time during their juvenile stage, and are still immature at 3 years of age. Immature fish showed a sex-dimorphic pattern; all the genes studied displayed a higher expression level in male gonads. We took advantage of the presence of juvenile fish with pre- and post-differentiated gonads (16 and 18 months old) to characterise them at the molecular level. The post-differentiated fish displayed a sex dimorphism of gene expression in their gonads for all genes studied, with the exception of sox9. The trends in undifferentiated fish lead us to propose that sturgeons undergoing male differentiation express high levels of Sertoli cell factors (dmrt1, sox9) and of genes involved in the production and receptivity of androgens (cyp17a1, star and ar) together with lh. Expression profiles and phylogenetic studies suggest that these genes are potential regulators of testis development in the Siberian sturgeon.

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.