title: Enzymes of steroid hormone metabolism in ovarian tissue of teleosts.
abstract: 1. Substrate-velocity kinetics and some other characteristics of three enzymes involved in steroid hormone metabolism in the ovary of the common carp, Cyprinus carpio and of the grey mullet, Mugil cephalus were determined. 2. Labeled steroid products of the enzyme reactions were identified by thin-layer and gas-liquid chromatographies, as well as by formation of derivatives. 3. 5 alpha-Steroid reductase of carp ovary was found to have a Michaelis-Menten constant undistinguishable from that of rat ovarian tissue, while the Km of the enzyme in mullet ovarian tissue was found to be different. 4. The Km of 20 alpha-hydroxysteroid dehydrogenase of mullet ovarian tissue was similar to the value reported for mammalian gonadal tissue, but the constant for 17 beta-hydroxy-steroid dehydrogenase in the carp ovary was different. 5. It is for the first time that these enzymes of steroid hormone metabolism have been quantitatively determined in teleost ovarian tissue.
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D015089:20-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism; D000818:Animals; D002347:Carps / Q000378:metabolism; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D005260:Female; D005399:Fishes / Q000378:metabolism*; D010053:Ovary / Q000201:enzymology*; D013256:Steroids / Q000378:metabolism*
chemical_list: D013256:Steroids; D015067:17-Hydroxysteroid Dehydrogenases; D015089:20-Hydroxysteroid Dehydrogenases; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase