Isolation and characterization of two distinct gonadotropins from chum salmon pituitary glands

• Published in: General and comparative endocrinology Vol. 71; no. 2; pp. 292 - 301
• Main Authors: Suzuki, Kunimasa, Kawauchi, Hiroshi, Nagahama, Yoshitaka
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.08.1988; Elsevier
• Subjects: Animals; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Glycoproteins - analysis; Glycoproteins - physiology; Gonadotropins - isolation & purification; Oncorhynchus keta; Pituitary Gland - analysis; Salmon - metabolism; Salmonidae; Vertebrates: endocrinology
• ISSN: 0016-6480; 1095-6840
• DOI: 10.1016/0016-6480(88)90257-2

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-17β 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.