AJP - Gastrointestinal and Liver Physiology, Vol 265, Issue 4 672-G676, Copyright © 1993 by American Physiological Society
Nutrient feedback inhibition of gastric emptying plays a larger role than osmotically dependent duodenal resistance
H. C. Lin, J. D. Elashoff, Y. G. Gu and J. H. Meyer
Department of Medicine, Cedars-Sinai Research Institute, Cedars-Sinai Medical Center, Los Angeles 90048.
The slowing of gastric emptying by hyperosmolar solutions has been
postulated to result from the triggering of duodenal osmoreceptor feedback
on the stomach. We tested the idea that the inhibition of gastric emptying
by a hyperosmolar solution depended on the duodenal resistance and the
triggering of nutrient-specific feedback by tracking gastric emptying of
300 and 1,200 mosmol/kgH2O test solutions in 12 dogs in which duodenal
resistance was either removed (by temporarily diverting chyme from uncorked
duodenal fistula) or preserved (by keeping duodenal fistula corked).
Mannitol was used to test osmolality alone, and glucose was used to examine
the combined effects of osmolality and nutrient-specific inhibitory
feedback. We found that: 1) the slowing effect of hyperosmolality was more
marked with the duodenal resistance preserved (P < 0.05; analysis of
variance), 2) the slowing effect of glucose was greater than that of
mannitol for all conditions (P = 0.01; analysis of variance), and 3) the
inhibitory effect of mannitol was localized to the duodenum. We conclude
that inhibition of gastric emptying by hyperosmolar mannitol depended
primarily on duodenal resistance, while the inhibitory effect of
hyperosmolar glucose depended on nutrient-specific feedback on the stomach
more than duodenal resistance.
