2013 Fiscal Year Final Research Report

Involvement of gonadotropin in snout extension in the Japanese minnow during ovulation

Research Project

Project/Area Number	23580263
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	General fisheries
Research Institution	Kitasato University
Principal Investigator	CHIBA hiroaki 北里大学, 海洋生命科学部, 准教授 (50236816)
Co-Investigator(Kenkyū-buntansha)	MORIYAMA Shunsuke 北里大学, 海洋生命科学部, 教授 (50222352)
Project Period (FY)	2011 – 2013
Keywords	アブラハヤ / 排卵 / 吻部 / 生殖腺刺激ホルモン / 結合組織 / 受容体
Research Abstract	In this study,to elucidate the mechanism of snout extension in the Japanese minnow, we examined the morphological changes during oocyte maturation and ovulation, both in vivo and in vitro. Fish injected with Human Chorionic Gonadotropin (HCG) ovulated and showed an increase in the rate of extension of snout length. Histological observation indicated that HCG-induced snout extension was accompanied by a marked expansion of irregular material in the connective tissue. Wet and dry weight measurements indicated that water accumulation during ovulation was the major factor contributing to the increase in snout volume. HCG also caused an increase in the weight of snout fragments in vitro. The results suggest that GTHinduces extension fo snout length through absorption of water in the connective tissue, the offering new insights into the function of GTH in reproduction.

(4 results)