THE GALANIN ANTAGONIST, M-15, INHIBITS GROWTH-HORMONE RELEASE IN RATS

The neuropeptide, galanin, has been implicated in the regulation of ra t growth hormone (rGH) release. In the present study, adult male rats were implanted dually with cannulae to the lateral cerebral ventricle and the right atrium. After surgical recovery, rats were infused with M-15, a specific galanin antagonist, into the lateral ventricle. Durin g the course of this brain infusion, rats were subjected to serial blo od sampling with red cell and artificial plasma replacement under stre ss-free conditions. Plasma was saved for rGH assay. Treatment with M-1 5 reduced rGH pulse amplitude and pulse frequency when compared to veh icle-infused controls. These data suggest that brain galanin participa tes in the ongoing stimulation of pulsatile rGH release in the adult m ale rat.