Glucocorticoids facilitate mineralocorticoid-induced sodium intake in the rat

We confirm and extend the finding that glucocorticoids facilitate mineralocorticoid-induced sodium intake in the rat. First, we report that subcutaneous injections of dexamethasone (DEX) increase deoxycorticosterone-induced sodium intake. Second, we demonstrate that continuous intravenous infusions of either DEX or corticosterone or the TYPE II glucocorticoid receptor agonist RU28362 increases the sodium intake of aldosterone-treated rats. And third, we measured urine sodium loss and found that rats were in positive sodium balance while receiving aldosterone and the glucocorticoid agonist, suggesting that the increased intake of sodium was primary to renal sodium loss. When taken together with the fact that glucocorticoids can increase the TYPE I aldosterone-preferring receptor population in the brain, the results suggests a role for the glucocorticoid hormones in the arousal of sodium appetite in the rat.