Plasma renin activity, water excretion and the decay of injected hormones and hormonal effects in rats with protein energy malnutrition.

Plasma renin activity was found to be correlated positively with muscle water content and the presence of oedema in rats with protein energy malnutrition, whereas the muscle potassium content showed a negative correlation with muscle water content. Malnourished rats also showed an inability to dispose of a water load. Nevertheless, the ability of malnourished rats to excrete injected hormones and to clear the plasma of bromosulphthalein proved to be normal. It is therefore concluded that, although the inability to balance consumption and excretion of water may in part be the result of increased effective plasma renin activity, the increased plasma concentration results from increased secretion rather than from decreased inactivation.