Deoxycorticosterone Acetate-Induced Renin Suppression in the Absence of Antidiuretic Hormone

Sprague-Dawley rats and Brattleboro rats homozygous and heterozygous for hereditary diabetes insipidus were treated with deoxycorticosterone acetate (DOCA; 100 mg/kg) for periods of up to 2 weeks and the activities of renin in plasma (PRA) and kidney tissue (RRA) were measured. PRA decreased dramatically in all groups within 4 days of DOCA treatment, suggesting that the presence of antidiuretic hormone (ADH) is not necessary for DOCA-induced renin suppression. After 11 and 14 days of treatment, PRA was suppressed less in the homozygous diabetes insipidus rats than in the other two groups, suggesting that the lack of ADH alters the response of PRA to DOCA treatment in the chronic state. RRA was not changed by DOCA treatment in any group, thus demonstrating that the initial response of the renin-angiotensin system to DOCA treatment is a suppression of secretion. These results suggest that the initial response of the renin-angiotensin system to DOCA is not dependent on the presence of ADH.