Effects of LHRH and LHRH-A on plasma GtH levels and maturation/ovulation in the common carp, Cyprinus carpio, kept under various environmental conditions
1984
Billard, Roland | Bieniarz, K. | Peter, R.E. | Sokolowka, M. | Weil, Claudine | Crim, L.W. | Institut National de la Recherche Agronomique (INRA) | Laboratoire de physiologie des poissons ; Institut National de la Recherche Agronomique (INRA) | Department of Ichthyobiology and Fisheries ; Academy of Agriculture | Department of Zoology ; Auburn University (AU) | Marine Sciences Research Laboratory ; Memorial University of Newfoundland = Université Memorial de Terre-Neuve [St. John's, Canada] (MUN)
Experiments were carried out to determine if some environmental factors usually present in spawning ponds at the time of ovulation could potentiate the effects of LHRH or LHRH-A on the plasma level of GtH, oocyte maturation or ovulation in the common carp, Cyprinus carpio. In one experiment females were held in the absence of a male in cages placed in rearing ponds containing a dense population of unicellular algae; the cages touched the bottom but there was no vegetation inside the cages. When LHRH-A was given in two injections (the first 5 μg/kg, the second, 6 h later, 50 μg/kg) plasma GtH was increased and followed oocyte maturation. Ovulation occurred in 50% (3 of 6) of the females. In another experiment, using a similar LHRH-A treatment schedule, the females were held in aquaria with added vegetation to serve as a spawning substrate; in such a simplified environment the effect of LHRH-A was not potentiated. Similarly, the natural environment of spawning ponds including the presence of males was of no benefit to the response to low doses of LHRH or LHRH-A when the water temperature was low (12°C). These results suggest that some undetermined environmental factors besides vegetation present in a pond situation may potentiate the effect of LHRH-A, possibly via abatement of the action of an endogenous gonadotropin release-inhibitory factor.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
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