长臀脑垂体和血清中促性腺激素的生殖周期变化

Changes in the pituitary and serum gonadotropin levels of Cranoglanis bouderius were studied at different stages of ovarian development. Based on African catfish gonadotropin (cfGTH) and its anti-serum (Racf), heterologous radio-immunoassay (RIA) for the gonadotropin (GTH) of Cranoglanis bouderius was developed. The pituitary GTH contents at the late development stage were significantly higher than that at the mature, ovulation or regressed stages, while serum GTH levels at maturation and ovulation were significantly higher than that at late development and regressed stages. Injection of gonadotropin-releasing hormone analogue (GnRH-A) stimulated GTH secretion. Domperidone (DOM) had no effect on the basal serum GTH level. Injection of GnRH-A and DOM significantly enhanced the GTH levels stimulated by GnRH-A alone. These results indicate that GTH release in Cranoglanis bouderius is under the dual regulation of gonadotropin releasing hormone (GnRH) and dopamine (DA) from the hypothalamus, but DA can only inhibit GTH release induced by GnRH and not basal GTH release.