title: Isolation and characterization of two distinct gonadotropins from the pituitary gland of Mediterranean yellowtail, Seriola dumerilii (Risso, 1810).
abstract: Two gonadotropins, GTH I and GTH II, were isolated and chemically characterized from the pituitary of Mediterranean yellowtail. They were extracted with 35% ethanol-10% ammonium acetate, separated by ion-exchange chromatography on a DE-52 column, and purified by reversed-phase high-performance liquid chromatography on Asahipak C4P-50 and subsequently by gel filtration chromatography on Superdex 75. The molecular weights were estimated at 47 kDa for GTH I and 29 kDa for GTH II by SDS-PAGE and at 49 kDa for GTH I and 42 kDa for GTH II by gel filtration. GTH II was completely dissociated, while GTH I was partially dissociated into alpha- and beta-subunits by treatment with 0.1% trifluoroacetic acid. The complete amino acid sequences of GTH alpha-, GTH I beta-, and GTH II beta-subunits were determined. The GTH alpha-subunit consisted of 91 amino acid residues. The GTH I beta and GTH II beta consisted of 105 and 115 amino acid residues, respectively, and had a 28% sequence identity to each other. They had the highest sequence identity with the respective gonadotropin subunits of bonito, tuna, and striped bass: 81-83% for GTH alpha, 67-71% for GTH I beta, and 91-93% for GTH II beta. The sequence identity of the GTH alpha-subunit with those of other teleosts and human and bovine LH and FSH was 57-67%. The GTH I beta-subunit showed a low sequence identity with other known fish GTH I beta s (36-51%) and was more similar to human and bovine FSH beta s (34% identity) than to human and bovine LH beta s (29% identity). The sequence identity of the GTH II beta-subunit with those of other teleosts was higher (60-73%), being more similar to LH beta s (43% identity) than FSH beta s (38% identity). Thus, two distinct gonadotropins, GTH I and GTH II, homologous to mammalian FSH and LH, respectively, are synthetized by M. yellowtail pituitary glands.
authors.affiliation: Department of Cell Biology, Faculty of Biology, University of Murcia, Spain.
authors.forename: M P
authors.initials: MP
authors.lastname: García-Hernández
authors.forename: Y
authors.initials: Y
authors.lastname: Koide
authors.forename: M V
authors.initials: MV
authors.lastname: Díaz
authors.forename: H
authors.initials: H
authors.lastname: Kawauchi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005399:Fishes / Q000378:metabolism*; D005640:Follicle Stimulating Hormone / Q000737:chemistry; D037201:Follicle Stimulating Hormone, beta Subunit; D006065:Gonadotropins, Pituitary / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D007986:Luteinizing Hormone / Q000737:chemistry; D008297:Male; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000737:chemistry*
chemical_list: D037201:Follicle Stimulating Hormone, beta Subunit; D006065:Gonadotropins, Pituitary; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone