IMMUNOLOCALIZATION OF STEROIDOGENIC ENZYMES (P450SCC, P450C17, P450AROM, AND 3-BETA-HSD) IN IMMATURE AND MATURE TESTES OF RAINBOW-TROUT (ONCORHYNCHUS-MYKISS)

We examined the localization of steroidogenic cells in rainbow trout ( Oncorhynchus mykiss) testis during spermatogenesis by using polyclonal antibodies generated against rainbow trout cholesterol side-chain cle avage enzyme cytochrome P450 (P450scc), 3 beta-hydroxysteroid dehydrog enase (3 beta-HSD), 17 alpha-hydroxylase/C17,21 lyase (P450c17), and a romatase cytochrome P450 (P450arom) as markers of steroid production. Since we had previously produced specific antibodies against 3 beta-HS D and P450arom, antibodies against oligopeptides corresponding to C-te rminal sequences of P450scc and P450c17, pre dieted from rainbow trout P450scc and P450c17 cDNAs, were produced in this study. These two ant ibodies recognized 54-kDa (P450scc) and 59-kDa (P450c17) bands specifi cally in several steroidogenic organs, i.e., testis, ovary, and interr enal tissue (head kidney) in Western blots. Immunohistochemically, imm unoreactive P450scc, P450c17, and 3 beta-HSD, but not P450arom, were f ound only in interstitial Leydig cells of immature and mature testes. Immunoreactive P450arom was not detected in either testis. This study suggests that Sertoli cells and germ cells of rainbow trout testis do not contain P450scc, P450c17, P450arom, or 3 beta-HSD.