title: Steroid production by amago salmon (Oncorhynchus rhodurus) testes at different development stages.
abstract: Developmental changes in the steroidogenic capacity of amago salmon (Oncorhynchus rhodurus) testicular fragments at six different stages during spermatogenesis and spermiation were examined using 18-hr incubations. Although both basal and chum salmon gonadotropin (SGA)-induced production of 11-ketotestosterone (11-ketoT) and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) remained relatively low in testicular fragments isolated in August (GSI 1.06; primarily spermatocytes and spermatids in the testes) and September (GSI 2.33-4.85; many spermatids and spermatozoa in the testes), 11-ketoT production was two to three times higher than 17 alpha,20 beta-diOHprog production. In mid October (GSI 4.31; primarily spermatozoa in the testes, with a few spermatids remaining), SGA greatly stimulated 11-ketoT production with no further stimulation in late October (GSI 3.54; advanced spermiation). In contrast, SGA dramatically increased 17 alpha,20 beta-diOHprog production in late October and November (GSI 3.02), coincident with the period of active spermiation. A time course study showed that SGA caused a marked increase in production of 17 alpha,20 beta-diOHprog within the first 3 hr. Testes collected in August and September produced a considerable amount of 17 alpha,20 beta-diOHprog in the presence of an exogenous precursor, 17 alpha-hydroxyprogesterone. These results indicate that a shift in steroidogenesis from 11-ketoT to 17 alpha,20 beta-diOHprog occurs in the amago salmon testis immediately prior to or during the spermiation period and further suggest that mechanisms of gonadotropin action on 17 alpha,20 beta-diOHprog production in testes differ from those of ovaries (Y. Nagahama, 1987, Dev. Growth Differ. 29, 1-12).
authors: Noto Marine Laboratory, Kanazawa University, Ishikawa, Japan.
authors: N
authors: N
authors: Sakai
authors: H
authors: H
authors: Ueda
authors: N
authors: N
authors: Suzuki
authors: Y
authors: Y
authors: Nagahama
mesh_terms: D000818:Animals; D012739:Gonadal Steroid Hormones / Q000096:biosynthesis*; D006062:Gonadotropins / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D011374:Progesterone / Q000096:biosynthesis; D011863:Radioimmunoassay; D012474:Salmon; D012621:Seasons; D013091:Spermatogenesis / Q000187:drug effects; D013737:Testis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis / Q000031:analogs & derivatives
chemical_list: D012739:Gonadal Steroid Hormones; D006062:Gonadotropins; D013739:Testosterone; D011374:Progesterone; C003600:11-ketotestosterone