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

在本研究中，我们观察了在体内和体外卵母细胞成熟和排卵过程中的形态变化，以阐明日本小鱼鼻子伸展的机制。注射人绒毛膜促性腺激素(HCG)的鱼排卵，并表现出鼻长延长率的增加。组织学观察表明，人绒毛膜促性腺激素诱导的鼻部扩张伴随着结缔组织中不规则物质的显着扩张。湿重和干重测量表明，排卵过程中水分的积累是导致口鼻体积增加的主要因素。人绒毛膜促性腺激素还可使体外培养的鼻部碎片重量增加。结果表明，GTH通过吸收结缔组织中的水分而导致鼻长的延长，为GTH在生殖中的作用提供了新的见解。

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.