Intracerebroventricular and intravenous administration of growth hormone secretagogue L-692,585, somatostatin, neuropeptide Y and galanin in pig: dose-dependent effects on growth hormone secretion.

Abstract Central regulation of growth hormone (GH) secretion by the GH secretagogue, L-692,585 (585), was determined in Yorkshire barrows (40–45 kg BW) with intracerebroventricular (icv) stainless steel cannulas placed by stereotaxic coordinates and indwelling external jugular vein (iv) cannulas for injecting 585 or saline during 3 h serial blood sampling. Dose-dependent effects of 585 were determined by icv injections of saline vehicle, 3, 10, and 30 μg/kg BW by once daily increment. A switchback study of iv and icv 585 treatment determined central and peripheral regulation of GH secretion by the secretagogue at 30 μg/kg BW. When administered icv, 585 increased GH concentration in a dose-dependent manner, with a return to baseline by 60 min. GH secretion was attenuated by increased numbers of icv 585 injections ( p  p  p  p  p  p