Response of rat jejunum to changes in sodium and volume balance.
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.
D000315:Adrenalectomy; D000450:Aldosterone / Q000097:blood; D000818:Animals; D001810:Blood Volume / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology; D004032:Diet; D004656:Enalapril / Q000494:pharmacology; D005110:Extracellular Space / Q000187:drug effects / Q000502:physiology*; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000502:physiology*; D008297:Male; D009392:Nephrectomy; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D012964:Sodium / Q000008:administration & dosage / Q000172:deficiency / Q000494:pharmacology*
D012710:Serum Albumin, Bovine; D000450:Aldosterone; D004656:Enalapril; D002216:Captopril; D012964:Sodium; D012083:Renin