EFFECTS OF GALANIN ON THE RAT PITUITARY-ADRENOCORTICAL AXIS

A subcutaneous bolus injection of 2 mu g galanin (GAL) acutely raised plasma concentrations of ACTH and corticosterone in adult Wistar rats. Conversely, a prolonged subcutaneous infusion of GAL (2 mu g/day) for 1, 2 or 4 days did not evoke changes either in adrenal and pituitary weights or in the blood levels of ACTH and corticosterone. These findi ngs suggest that GAL is involved in the acute positive regulation of t he function of the hypothalamo-pituitary-adrenocortical axis in rats. The co-localization of GAL with CRH and ACTH in the neurons of the par aventricular nucleus and in the pituitary corticotropes, respectively, may provide the basis for this type of functional control.