Growth hormone inhibits the hypophysectomy induced expression of galanin in hypothalamic neurons of the toad (Bufo arenarum Hensel)

GONZALEZ NICOLINI, V., A.A. OREZZOLI, M.V., M.J. VILLAR AND J.H. TRAMEZZANI

GENERAL AND COMPARATIVE ENDOCRINOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 1997 vol. 105 p. 323 - 332

0016-6480

Abstract The expression of the neuropeptide galanin was analyzed by immunohistochemistry in magnocellular and preoptic hypothalamic neurons of toads following hypophysectomy (HPX) and pars distalectomy (PDX). There was a marked increase in the galanin-like immunoreactive expression in magnocellular hypothalamic cells 3 days after HPX, followed by a decrease to normal levels after 7 days. No changes in the expression of galanin were detected after PDX in these neurons when compared to controls. Moreover, 7 days after HPX or PDX the number of cells expressing galanin was significantly increased in the preoptic area, where numerous intraependymal cells were intensely immunoreactive. The hypophysis grafts into the hind limb in HPX or PDX animals prevented increased galanin-like immunoreactivity in preoptic cells but not in magnocellular neurons. Similarly, PDX toads given growth hormone showed no GAL-LI in the intraependymal preoptic cells. These results suggest the presence of a region regulation of galanin expression in the preoptic area by hypophyseal hormones, in particular growth hormone. PMID: 9073494 [PubMed - indexed for MEDLINE]