Effect of Gonadotropin Hormone-Releasing Hormone Analogs on the Gonadotropin Secretion by the Pituitary of Helmet Catfish (Cranoglanis bouderius) in vitro

The gonadotropin (GTH) secretion from pituitary fragments of helmet catfish (Cranoglanis bouderius) was studied by a perfusion incubation system and GTH radiommunoassay (RIA).The results showed that chronic administration of gonadotropin hormone-releasing hormone analogs (GnRH-A) was able to stimulate GTH release from pituitary fragments in vitro,which was consistent to African catfish (Clarias gariepinus) and catfish (Silurus asotus).The insensitivity to chronic administration of GnRH-A was not be observed in the helmet catfish，which was consistent to catfish and African catfish，but different from that in goldfish (Carassius auratus) and Cyprinus carpio haematopters.Repetitive pulse administration of GnRH-A was also able to stimulate GTH release from the pituitary fragments in dose-dependent manner in helmet catfish.These results showed that chronic administration of GnRH-A could have an effect on artificial propagation of helmet catfish.