AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 3 413-G420, Copyright © 1986 by American Physiological Society
Response of rat jejunum to changes in sodium and volume balance
N. R. Levens
Initial studies determined whether a renal factor facilitates decreased
jejunal absorption following volume expansion of the anesthetized rat.
Volume expansion (VE) decreased jejunal absorption to the same extent in
both normal and nephrectomized animals. Furthermore, VE of a donor animal
failed to alter jejunal absorption in a recipient following cross
circulation. Thus, a hormonal factor is not implicated in the jejunal
response to VE. Additional experiments demonstrated that rats ingesting a
high-Na diet exhibited levels of jejunal absorption lower than animals fed
a normal-Na diet. High-Na animals were not volume expanded. Plasma
aldosterone concentrations and plasma renin activity were reduced in
high-Na animals. Bilateral adrenalectomy-nephrectomy inhibited jejunal
absorption. However, neither bilateral adrenalectomy nor bilateral
nephrectomy alone inhibited jejunal absorption. Furthermore, inhibition of
angiotensin formation in adrenalectomized animals failed to alter jejunal
absorption. Decreased jejunal absorption in high-Na animals is not due to
volume expansion or to inhibition of the renin-angiotensin-aldosterone
axis.
