AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 2 268-R273, Copyright © 1988 by American Physiological Society

ARTICLES

Effect of teleost GnRH on reinitiation of oocyte meiosis in goldfish, in vitro

H. R. Habibi, G. Van der Kraak, E. Bulanski and R. E. Peter
Department of Zoology, University of Alberta, Edmonton, Canada.

The effects of native and an agonist analogue of teleost gonadotropin-releasing hormone (GnRH) [(D-Arg6, Trp7, Leu8, Pro9-NHEt)-GnRH; tGnRH-A] on the hormone-induced meiotic maturation of goldfish oocytes were investigated. Incubation of follicle-enclosed goldfish oocytes with either carp gonadotropin (GtH) or meiogenic progestogens, including 17 alpha-hydroxyprogesterone (HP) and 17 alpha,20 beta-dihydroxyprogesterone (DHP), reinitiated oocyte meiosis in vitro, as indicated by germinal vesicle dissolution (GVD). Addition of tGnRH-A (10(-7) M) significantly attenuated the GVD response to GtH, HP, and DHP in a dose-related fashion; tGnRH-A reduced the magnitude of progestogen-induced GVD response without significantly affecting the sensitivity of the oocytes to the meiogenic steroids. Similarly, administration of native teleost GnRH (tGnRH) significantly attenuated GtH-induced GVD response, although the 50% maximal response of the native peptide was significantly higher than that of tGnRH-A (380.9 +/- 125 and 2.72 +/- 0.94 nM, respectively). The present results provide the first demonstration of an inhibitory action of a GnRH agonist on the process of progestogen-induced oocyte meiosis and support the hypothesis that GnRH or a GnRH-like peptide might play a modulating role in the control of oocyte meiosis at the ovarian level in goldfish.

This article has been cited by other articles:

				D. Pati and H. R. Habibi Involvement of Protein Kinase C and Arachidonic Acid Pathways in the Gonadotropin-Releasing Hormone Regulation of Oocyte Meiosis and Follicular Steroidogenesis in the Goldfish Ovary Biol Reprod, March 1, 2002; 66(3): 813 - 822. [Abstract] [Full Text] [PDF]