caa a22 4500 477117392 CHVBK 20180405111626.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF01875594 doi (NATIONALLICENCE)springer-10.1007/BF01875594 Gonadotropins I and II do not stimulate the in vitro secretion of 17α,20β-dihydroxy-4-pregnen-3-one 20-sulphate by rainbow trout gonads during final sexual maturation [Elektronische Daten] [J. Nagler, A. Scott, C. Tyler, J. Sumpter] Thein vitro secretion of 17α,20β-dihydroxy-4-pregnen-3-one 20-sulphate (17α,20β-P-sulphate) and the free steroid 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-P), by rainbow trout (Oncorhynchus mykiss) gonads, in response to gonadotropin (GTH) I and GTH II, were studied during the final stages of sexual maturation. Substantial amounts of 17α,20β-P-sulphate were produced, by both mature ovaries and testes, indicating considerable 20β-hydroxysteroid sulphotransferase (20β-HST) activity within these tissues. In the post-ovulatory ovary the level of 17α,20β-P-sulphate (36.6 ng ml−1) greatly exceeded that of 17α,20β-P (8.59 ng ml−1). The amount of 17α,20β-P-sulphate produced in incubations of both mature ovary and testes was unaffected by either GTH I or GTH II treatment at physiological concentrations up to 100 ng ml−1. Similarly, incubations of maturing ovary and testes, treated with GTH I or GTH II, in the presence of added 17α,20β-P at 100 ng ml−1 of medium, produced levels of 17α,20β-P-sulphate that were similar to those of the controls. In incubations of mature ovarian follicles at the stages of germinal vesicle breakdown and preovulation, both GTHs significantly stimulated secretion of 17α,20β-P, although GTH II was always more potent than GTH I. GTH II significantly elevated the levels of 17α,20β-P in testicular incubations from mature males more than 4-fold relative to GTH I and controls, which did not differ from one another. In conclusion, 20β-HST, the enzyme responsible for the sulphate conjugation of 17α,20β-P, was found to be active in the ovaries and testes of rainbow troutin vitro. However, the levels of this enzyme do not appear to be regulated by either GTH I or GTH II. Kugler Publication bv Amsterdam, 1996 17α,20β-P-sulphate nationallicence maturation nationallicence gonadotropin nationallicence rainbow trout nationallicence Nagler J. Department of Biology and Biochemistry, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK aut Scott A. Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research, Fisheries Laboratory, NR33 OHT, Lowestoft, Suffolk, UK aut Tyler C. Department of Biology and Biochemistry, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK aut Sumpter J. Department of Biology and Biochemistry, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK aut Fish Physiology and Biochemistry Kluwer Academic Publishers 15/2(1996-04-01), 149-156 0920-1742 15:2<149 1996 15 10695 https://doi.org/10.1007/BF01875594 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01875594 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nagler J. Department of Biology and Biochemistry, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK aut NATIONALLICENCE 700 1- Scott A. Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research, Fisheries Laboratory, NR33 OHT, Lowestoft, Suffolk, UK aut NATIONALLICENCE 700 1- Tyler C. Department of Biology and Biochemistry, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK aut NATIONALLICENCE 700 1- Sumpter J. Department of Biology and Biochemistry, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK aut NATIONALLICENCE 773 0- Fish Physiology and Biochemistry Kluwer Academic Publishers 15/2(1996-04-01), 149-156 0920-1742 15:2<149 1996 15 10695 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer