Influence of feeding on growth hormone secretion and response to growth hormone-releasing factor in sheep.
This study was designed to examine the effects of feeding and factors associated with feeding on growth hormone (GH) secretion and response to growth hormone-releasing factor (GHRF) in sheep. Feeding reduced (P less than 0.05) plasma GH concentrations to 60% of prefeeding concentrations within 45 min. Allowing the animals to anticipate being fed or artificial distention of the cranial sac of the rumen with a water-filled balloon did not significantly reduce plasma GH. Feeding, distention of the rumen and anticipation of being fed each reduced (P less than 0.05) the GH response to intravenous injection of 0.067 micrograms GHRF/kg body weight. It is concluded that GH secretion is reduced within 15 min after feeding in ruminants and that part of the reduced secretion may be the result of reduced response to GHRF.
Trenkle
A
A
Department of Animal Sciences, Iowa State University, Ames 50011.
D000818:Animals; D004435:Eating; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D008297:Male; D009919:Orchiectomy; D011930:Reaction Time; D012417:Rumen / Q000502:physiology; D012756:Sheep / Q000502:physiology*
D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone