AJP - Endocrinology and Metabolism, Vol 248, Issue 1 101-E107, Copyright © 1985 by American Physiological Society
How laboratory dogs accommodate meals of different size but similar composition
M. Nomura, G. R. Greenberg, A. Bahoric, B. Zinman and A. M. Albisser
Healthy laboratory dogs appear to absorb a mixed meal from the gut at a
constant rate. This rate is apparently not affected by meal size. If this
is the case, then duration of absorption should depend on total or
integrated meal size, whereas metabolite and hormonal levels would be
independent of the number of feedings. To explore these hypotheses further,
we compared the metabolite and hormonal responses with a single mixed meal
and one divided in two halves, provided in two feedings 4 h apart. We
detected no effect of the second meal in the metabolic response levels of
glucose, lactate, pyruvate, alanine, free fatty acids, or 3-hydroxybutyrate
or the hormonal responses of insulin, pancretic glucagon, gastrin, or
secretin. Only minor differences were detectable in the hormonal response
levels of pancreatic polypeptide, gastric inhibitory peptide, and
enteroglucagon, consistent with a response to a second meal. We conclude
that the observed change in circulating metabolite or hormone concentration
is independent of the size of meal eaten, but the duration of the excursion
depends on meal size. Thus, during the bulk phase of nutrient uptake, the
absorption mechanism of the laboratory dog appears to be saturated.
