The levels of circulating vitellogenin in the plasma of male carp after induction by estradiol-17β was examined in summer- and winter-acclimatized fish. During the warm season male fish exhibited a clear vitellogenic response, whereas the fish adapted to the cold season did not. The evaluation of the hepatic estrogen receptors revealed that although steroid-binding affinity is not affected by seasonal acclimatization, the concentration of estrogen receptors certainly is. This was evidenced in estrogen treated fish. Summer-acclimatized carp featured a concentration of hepatic estrogen receptors 2.5 fold higher than the cold season adapted fish. The results suggest that the failure of estrogen to induce vitellogenesis in cold adapted carp may be due, at least in part, to a deficient up-regulation of hepatic estrogen receptors in the corresponding acclimatized state.
|Number of pages||9|
|Publication status||Published - 1992|
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