title: Annual changes in serum levels of two choriogenins and vitellogenin in masu salmon, Oncorhynchus masou.
abstract: Annual changes in serum levels of two chorion precursors, choriogenin H (Chg H) and choriogenin L (Chg L), vitellogenin (Vg) and estradiol-17beta (E2) were quantified in masu salmon, Oncorhynchus masou, using specific immunoassays. Serum Chg levels were higher than Vg during the previtellogenic growth phase when circulating E2 levels were low ( approximately 0.1 ng/mL), suggesting higher sensitivity of Chg to E2. When oocyte growth shifted to the vitellogenic phase, Vg levels increased and became the most abundant in serum coincident with elevations of E2 and GSI. Chg H, Chg L and Vg peaked 1 month prior to ovulation at 0.61+/-0.08, 0.98+/-0.18 and 10.93+/-3.24 mg/mL, respectively. These results suggest that chorion formation by Chgs occurs prior to vitellogenesis and that the sensitivity of Chgs to low circulating E2 is closely related to the sequential events of oocyte growth.
authors.affiliation: Division of Marine Biosciences, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Fujita
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Fukada
authors.forename: Munetaka
authors.initials: M
authors.lastname: Shimizu
authors.forename: Naoshi
authors.initials: N
authors.lastname: Hiramatsu
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hara
mesh_terms: D000818:Animals; D004527:Egg Proteins / Q000097:blood*; D004958:Estradiol / Q000097:blood; D007118:Immunoassay; D017683:Oncorhynchus / Q000097:blood*; D009865:Oocytes / Q000254:growth & development; D011498:Protein Precursors / Q000097:blood; D012621:Seasons; D014818:Vitellogenesis; D014819:Vitellogenins / Q000097:blood*
chemical_list: D004527:Egg Proteins; D011498:Protein Precursors; D014819:Vitellogenins; C104950:choriogenin H; D004958:Estradiol