Testicular steroidogenic enzymes in the lizard Podarcis sicula during the spermatogenic cycle.

Steroidogenic Acute Regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), 5α-Reductase (5α-Red), P450 aromatase are key enzymes involved in steroidogenesis. Recently, we showed the expression and the localization of P450 aromatase in Podarcis sicula testis during the different phases of the reproductive cycle, showing its involvement in the control of steroidogenesis, particularly in 17β-estradiol synthesis. Now, we have investigated the presence and distribution of the other enzymes involved in steroidogenesis, i.e. StAR, 3β-HSD, 17β-HSD and 5α-Red, during three significant periods of the reproductive cycle: summer stasis (July-August), autumnal resumption (November) and reproductive period (May-June). We demonstrated for the first time that all these enzymes are always present in somatic cells (Leydig and Sertoli) and germ cells (spermatogonia, spermatocytes I and II, spermatids and spermatozoa) of Podarcis testis, mainly in spermatids and spermatozoa. The present results strongly suggest that in Podarcis testis both somatic and germ cells could be involved in local sex hormone synthesis and that 5α-Red and P450 could carry out a pivot role.