Methallibure-induced inhibition of hypothalamo-hypophyseal-ovarian activity in the catfish Heteropneustes fossilis involves changes in hypothalamic monoamine activity |
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| Authors: | B Senthilkumaran KP Joy |
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| Institution: | (1) Department of Zoology, Banaras Hindu University, Varanasi, 221 005, India |
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| Abstract: | Administration of Methallibure, a non-steroidal gonadotropin (GTH) inhibitor 20  g g–1 body weight; i.p., daily for 10 days, to prespawning phase female Heteropneustes fossilis inhibited the brain-pituitary-ovarian axis as indicated by significant reductions in plasma and pituitary levels of GTH-II, and plasma levels of 17 -estradiol (E2) and testosterone. Concurrently, the treatment resulted in significant reductions in the hypothalamic content of serotonin, noradrenaline (and adrenaline) that stimulate, and a significant elevation of dopamine that inhibits GTH-II release in this species. Activities of the monoamine degrading enzymes, monoamine oxidase and catechol-O-methyltransferase were significantly increased, while that of the synthesizing enzymes, dopamine--hydroxylase and phenylethanolamine-N-methyltransferase were significantly decreased. These results suggest that the mechanism of inhibition of GTH-II secretion includes, among others, differential actions of the drug on hypothalamic monoamine metabolism. |
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| Keywords: | Methallibure gonadotropin-II secretion catfish monoamines 17 -estradiol" target="_blank">gif" alt="beta" align="MIDDLE" BORDER="0">-estradiol testosterone |
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