Isolation and characterization of two distinct gonadotropins from chum salmon pituitary glands.
Two distinct gonadotropins, GTH I and GTH II, were extracted with 35% ethanol-10% ammonium acetate, pH 6.1, from female chum salmon pituitary glands, and purified by ion-exchange chromatography on DE-52 and CM-Sephadex C-25 by stepwise elution, and gel filtration on Sephadex G-75. Gonadotropic activities of these preparations were demonstrated in vivo by stimulation of gonad growth in juvenile rainbow trout, and in vitro by enhancement of estradiol-17 beta production by amago salmon ovarian follicles. Molecular weights were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 50,000 and 36,000 for GTH I and GTH II, respectively. Both gonadotropins are glycoproteins composed of two distinct subunits with N-terminal amino acid residues of Tyr/Gly for GTH I, and Tyr/Ser for GTH II. These results suggest the presence in teleost fish of two chemically distinct gonadotropic glycoproteins.
Suzuki
K
K
Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Iwate, Japan.
Kawauchi
H
H
Nagahama
Y
Y
D000818:Animals; D005260:Female; D006023:Glycoproteins / Q000032:analysis / Q000502:physiology; D006062:Gonadotropins / Q000302:isolation & purification*; D010902:Pituitary Gland / Q000032:analysis*; D012474:Salmon / Q000378:metabolism*
D006023:Glycoproteins; D006062:Gonadotropins