Galanin stimulates growth hormone (GH) secretion via GH-releasing factor (GRF) in conscious rats

The possibility of a role of hypothalamic growth hormone (GH)-releasing factor (GRF) in GH secretion induced by centrally administered galanin was investigated in freely moving male rats. Intracerebroventricular (i.c.v.) injection of synthetic galanin (0.4 or 2 micrograms/rat) elicited a dose-related increase in plasma GH in these conscious rats. Pretreatment with rabbit antiserum specific for rat GRF significantly inhibited the plasma GH increase induced by i.c.v. injection of galanin (2 micrograms/rat). These findings suggest that galanin-induced GH secretion in the rat is mediated at least in part by hypothalamic GRF.