AJP - Gastrointestinal and Liver Physiology, Vol 246, Issue 5 627-G633, Copyright © 1984 by American Physiological Society
Insulin and islet cell transplant--effect on intestinal uptake of lipids
A. B. Thomson and R. V. Rajotte
A previously validated in vitro technique was used to determine the effect
of once-daily injections of NPH insulin (NPH) and islet cell transplant
(ICT) on the enhanced uptake (Jd) of lipids into the intestine of diabetic
rats. Three months after ICT, the urine volume, urine glucose, and fasting
blood sugars were near normal. The Jd of lauryl alcohol was used to measure
the effective resistance of the unstirred water layer (UWL); NPH was
associated with an increase in UWL in the jejunum when the bulk phase was
stirred or unstirred and a rise in UWL in the ileum when the bulk phase was
unstirred but had no effect on UWL in the colon. The Jd of a homologous
series of saturated medium-chain-length fatty acids in untreated diabetic
rats was reduced with NPH and ICT. The Jd of cholesterol was lower in
diabetic rats treated with NPH or ICT than in untreated diabetic rats over
a wide range of concentrations of cholesterol, bile acid, and bile
acid/cholesterol. The colon was less permeable than the jejunum to fatty
acids or fatty alcohols. In contrast to the small intestine, diabetes had
no effect on colonic uptake of these probes. Thus, injection of exogenous
insulin or endogenous insulin supplied by ICT in diabetic rats reduced the
Jd of lipids, normalized the effective resistance of the UWL, and reduced
the enhanced passive permeability of the jejunum observed in diabetic
animals.
