Deficient inactivation of cortisol by 11 beta-hydroxysteroid dehydrogenase in essential hypertension.

OBJECTIVE

11 beta-Hydroxysteroid dehydrogenase protects renal mineralocorticoid receptors from cortisol by converting cortisol to inactive cortisone. 11 beta-Dehydrogenase deficiency, either congenital or after inhibition by liquorice and carbenoxolone, results in cortisol-dependent mineralocorticoid excess and hypertension. We tested the hypothesis that the same mechanism occurs in some patients with essential hypertension.

DESIGN/PATIENTS: Twenty patients with essential hypertension were compared with 19 matched healthy controls.

MEASUREMENTS

11 beta-Hydroxysteroid dehydrogenase activity was assessed by the half-life of 11 alpha-3H-cortisol, and by the ratios of cortisol to cortisone in plasma and of their metabolites in urine. Renal mineralocorticoid receptor activation was assessed by plasma potassium, renin activity and aldosterone.

RESULTS

Half-lives of 11 alpha-3H-cortisol were prolonged in a subgroup of hypertensives (mean +/- SE 53.2 +/- 3.6 min in hypertensives vs 42.3 +/- 2.3 in controls, P < 0.05; seven of the 20 hypertensives had half-lives exceeding 2 SD of controls). Ratios of cortisol to cortisone in plasma and of their metabolites in urine were not different. 11 alpha-3H-Cortisol half-lives correlated with blood pressure but not with indices of renal mineralocorticoid receptor activation.

CONCLUSIONS

11 beta-Dehydrogenase is defective in a proportion of patients with essential hypertension. The normal ratios of cortisol to cortisone in plasma and of their metabolites in urine, also seen after carbenoxolone administration, suggest that 11 beta-reductase conversion of cortisone to cortisol is also defective. Unlike other syndromes of 11 beta-dehydrogenase deficiency, the defect was not associated with mineralocorticoid excess. We suggest that it may cause hypertension by increasing exposure of vascular steroid receptors to cortisol.