title: Steroidogenic activities of two distinct salmon gonadotropins.
abstract: The effects of salmon gonadotropins, GTH I and GTH II, on production of two major steroid hormones in female salmonid reproduction, estradiol-17 beta and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) were compared using amago salmon (Oncorhynchus rhodurus) intact ovarian follicles in vitro. In addition, the production of 17 alpha-hydroxyprogesterone (17 alpha-OHprog) by thecal layers and 17 alpha,20 beta-diOHprog by granulosa layers in response to GTH I and II was examined during oocyte maturation. Both GTHs enhanced estradiol-17 beta production by midvitellogenic ovarian follicles in a dose-dependent manner; there was no significant difference in potency between GTH I and II. In postvitellogenic follicles, GTH II appeared to be more effective in stimulating 17 alpha,20 beta-diOHprog production than GTH I. GTH II was also found to be more potent than GTH I in stimulating 17 alpha-OHprog production by thecal layers and 17 alpha,20 beta-diOHprog production by granulosa layers in the presence of 17 alpha-OHprog. Thus, GTH II appears to differ from GTH I showing a reproductively high specificity for 17 alpha,20 beta-diOHprog production during oocyte maturation.
authors.affiliation: Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Iwate, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Nagahama
authors.forename: H
authors.initials: H
authors.lastname: Kawauchi
mesh_terms: D019326:17-alpha-Hydroxyprogesterone; D000818:Animals; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D012739:Gonadal Steroid Hormones / Q000096:biosynthesis*; D006065:Gonadotropins, Pituitary / Q000502:physiology*; D006107:Granulosa Cells / Q000378:metabolism; D006908:Hydroxyprogesterones / Q000096:biosynthesis; D066298:In Vitro Techniques; D006080:Ovarian Follicle / Q000378:metabolism; D012474:Salmon / Q000378:metabolism*; D013799:Theca Cells / Q000378:metabolism
chemical_list: D012739:Gonadal Steroid Hormones; D006065:Gonadotropins, Pituitary; D006908:Hydroxyprogesterones; C007433:17,20-dihydroxy-4-pregnen-3-one; C057763:gonadotropin- pituitary, beta-subunit I, salmon; D004958:Estradiol; D019326:17-alpha-Hydroxyprogesterone