Water restricted rats exhibit a rapid decrease in plasma corticosterone after drinking. The present study examined the effect of restriction-induced drinking on plasma aldosterone, and on plasma clearance of corticosterone. Rats were water restricted for 6-7 days and then sacrificed prior to, or 15 min after water administration; plasma and adrenal hormones were assayed. Plasma and adrenal corticosterone decreased after drinking without a change in plasma corticosteroid-binding globulin; plasma ACTH decreased or did not change. In contrast, plasma aldosterone did not change, or increased after drinking; plasma renin activity was elevated by water restriction and increased further after drinking. In another experiment, rats were adrenalectomized (ADX), and corticosterone and aldosterone were replaced with pellets and osmotic mini-pumps, respectively. Rats were water restricted and sacrificed. There was a small decrease in plasma corticosterone, but no change in aldosterone after drinking in ADX animals. These data suggest changes in plasma steroids after restriction-induced drinking result from zone-specific responses of the adrenal to known secretagogues, with minimal contribution from increased plasma clearance.