AJP - Gastrointestinal and Liver Physiology, Vol 239, Issue 2 123-G127, Copyright © 1980 by American Physiological Society
Jejunal transport properties of piebald mouse model for Hirschsprung's disease
H. J. Cooke, H. J. Henning Jr, J. D. Wood and A. R. Cooke
Unidirectional fluxes of alanine, methionine, and Na were measured in
jejunal segments from 3- to 4-wk-old normal (N) mice or mice with
congenital (P) or induced (I) megacolon in the absence of electrochemical
gradients. Short-circuit currents were 286.8 +/- 16.3 and 302.1 +/- 32.6 mu
A/cm2 for P and I mice, respectively, and were approximately 1.5-2 times
greater than in N mice. Tissue conductances averaged 42.3 +/- 0.6 and 39.3
+/- 3.4 mS/cm2 for P and I mice, respectively, and were twice those found
in N mice. Net Na absorption was 2-3 times greater in P than N mice and was
increased by addition of alanine. Alanine and methionine were actively
absorbed and the net fluxes of alanine were 2-3 times greater in p and I
mice than in normals. Unidirectional alanine influx was enhanced in P and I
mice. Jmax of 9.7 +/- 2.6 and 14.2 +/- 1.0 micro M x cm-2 x h-1 were
obtained for N and P mice, respectively. These results show that the
transport properties of jejunal mucosa of mice with megacolon differ from
those of N mice. Mice with megacolon absorb alanine and Na at a greater
rate than N mice and the enhanced amino acid absorptive rate can be
explained by an increased alanine influx, probably due to an increased
number of active transport carriers.
