Effect of cholinergic blockade on inhibited gh secretion by feeding
and intraruminal scfa infusion in sheep.
Matsunaga, N., M. Wakiya, S. G. Roh, M. Hirota, M. L. He, S. Hidaka,
and H. Hidari.
Laboratory of Animal Production, Department of Animal Science,
Obihiro University of Agriculture and Veterinary Medicine, Inada-cho,
Obihiro 080, Japan
APStracts 4:0218E, 1997.
The effect of cholinergic blockade on suppressed GH secretion caused
by feeding or the intraruminal infusion of an acetate, propionate and
butyrate mixture (107 and 214 [circumflex]amol kg-1 min-1 over 6 h)
was examined in ovariectomized ewes. Intraruminal infusion at the
rate of 107 [circumflex]amol kg-1 min-1 increased peripheral plasma
SCFA concentrations to approximately the physiological levels noted
after feeding. Plasma GH was markedly suppressed by feeding and at
both the 107 and 214 [circumflex]amol kg-1 min-1 SCFA infusion rates,
however, cholinergic blocking agents completely blocked the
suppressed GH secretion after feeding and at the only 107
[circumflex]amol kg-1 min-1 infusion rate. Plasma glucose increased
at the both infusion rates and the plasma free fatty acids decreased
after feeding and at the both infusion rates. However, both
metabolites were unchanged relative to the saline control, following
the injection of the cholinergic antagonists. It is suggested that
the decrease in plasma GH observed after feeding and a near
-physiological ruminal SCFA increment is mediated via the
parasympathetic nerve and not by pharmacological ruminal SCFA
increments attributed to other pathways.
Received 30 April 1997; accepted in final form 18 September 1997.
APS Manuscript Number E200-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997