No abstract

Synthetic luteinizing hormone – releasing hormone was found to be effective in inducing ovulation in goldfish after three daily injections of 2 μg/g intracranially or of 10 μg/g intraperitoneally.

PANDEY, S. 1969. Effects of hypophysectomy on the testis and secondary sex characters of the adult guppy Poecilia reticulata Peters. Can. J. Zool. 47: 775-781.Hypophysectomy of the adult guppy causes marked regression in the testis, completely blocks mitosis in the spermatogonia, and prevents their wansformation into spermatocytcs. However, sperrnatocytes, spermatih, and s p c m already prcsent in the testis at the time of operation develop into spmnatophores. The spermatophores rupture after 8 weeks and the rrsullmp sperm are phagocyfosed within the sperm ducts. The epithelial cells llning the sperm ducts, the Sertoli cells, and the interstitial cells regrcw. Of two particularly well-differentiated secondary sex characters, the gonopod~um (modified anal fin) remains unaffected, white the patches of br~ght lipophores (vellow and red p~gments) present on the sides ol the body become fain1 or entirely disappear. IntroductionThe effects of hypophysectomy on the testes and secondary sex characters of teleosts have been reviewed by several investigators (Pickford and Atz

Synthetic luteinizing hormone – releasing hormone (LH–RH) induces ovulation and stimulates release of secretory granules from the pituitary gonadotrophs of goldfish kept at 12 ± 1 °C, a temperature at which ovulation does not occur in control fish. Gonadal development is stimulated at doses too low to induce ovulation. Relatively high doses were required to induce ovulation; this may be related to the low experimental temperatures, although several other possibilities are discussed. Intracranial injections appeared to be only slightly more effective than intraperitoneal injections. A single type of gonadotroph containing two types of granules was identified at the ultrastructural level. Only the small, electron-dense granules are released after injection of synthetic LH–RH; the role of the large, less electron-dense granules is uncertain.

Clomiphene citrate induced ovulation in gravid goldfish. The stripped eggs were viable and on fertilization developed into normal fry.