Increased renal sensitivity to aldosterone in the rat: induction by a high potassium diet

1. The renal response to aldosterone, measured by urinary sodium and potassium excretion, was determined in adrenalectomized rats that had been previously fed either a high potassium diet or a control diet. High K+ rats showed an enhanced response to aldosterone at all doses tested. 2. The induction of this enhanced response to aldosterone could be suppressed by a high sodium intake. It may also require the presence of the adrenal glands during the induction period, although interpretation of adrenalectomy experiments in the present study was made difficult by the effect of maintenance DOC therapy on the renal response to aldosterone. 3. The enhanced response could not be induced by a low sodium diet alone or by the administration of high doses of exogenous aldosterone. 4. No difference between high K+ and control rats could be detected in rat kidney mineralocorticoid receptors, assessed by both in vivo and in vitro binding of tritiated aldosterone. 5. The method of the induction, and the mechanism of the enhanced response remains to be defined.