鳗鲡繁殖生物学研究 Ⅳ.人工催熟过程中下海鳗鲡的GtH分泌活动、性腺发育状况和脑垂体GtH细胞的超显微结构

STUDIES ON THE BREEDING BIOLOGY OF THE EEL (ANGUILLA JAPONICA TEMMINCK & SCHLEGEL) Ⅳ. THE GONADOTROPIN SECRETION, GONADAL DEVELOPMENT AND ULTRASTRUCTURE OF GONADOTROPIC CELL OF THE EEL DURING PROCESS OF INDUCED MATURATION.

雌二醇通过正反馈作用能促进脑垂体促性腺激素(GtH)细胞的合成活动,使脑垂体GtH水平显著升高。促黄体素释放激素的类似物(LHRH-A)和利血平(reserpine,RES)能促进脑垂体GtH细胞的分泌活动,使血液中GtH含量显著升高。鲤垂体、人体绒毛膜促性腺激素(HCG)和LHRH-A三种激素混合进行多次注射能诱导雌雄鳗鲡性腺发育成熟,其催熟效果明显优于它们的分别单独多次注射或者鲤鱼脑垂体和HCG的多次注射,表明外源的和内源的促性腺激素对于诱导鳗鲡性腺发育成熟都是重要的。鳗鲡脑垂体GtH细胞超显微结构的观察证实它们在激素诱导性腺发育成熟过程中处于活跃的合成与分泌状态。

Estradiol stimulates hormonal synthesis of GtH cells through a positive feedback, leading to a significant increase in pituitary GtH content. Joint treatments with LHRH-A and reserpine result in a significant increase in serum GtH level after a pretreatment with estradiol. Joint treatments with carp pituitary homogenate, HCGand LHRH-A (des-Gly^(10)-D-Ala^6-LHRH-ethylamide) yield a better result on induced sexual maturation both in male and female eel than merely using carp pituitary homogenate or HCG. It indicates that both exogenous and endogenous gonadotropin are essential to the induction of sexual maturation of this fish. In mature eel, hypertrophied GtH cells, distinct degranulation and marked dilatation of cisternae of the rough endoplasmic reticulum, suggest the release of hormone from the GtH cells.