11 beta-Hydroxylase in mitochondrial fractions of functioning and non-functioning adrenocortical tumors

The activity of 11 beta-hydroxylase was investigated in the mitochondrial fractions of 19 surgically resected adrenocortical tumors associated with Cushing's syndrome (4 adenomas and 2 carcinomas), primary aldosteronism (8 adenomas), adrenogenital syndrome (AGS) (2 carcinomas) and no hormonal symptoms (3 adenomas). Five adrenal cortices from patients with mammary carcinoma, renal cell carcinoma and pheochromocytoma were used for the normal control. The activities of 11 beta-hydroxylation of deoxycorticosterone and of 11-deoxycortisol in the control adrenal cortices were 0.66-2.16 pmole/mg protein/min (mean: 1.28 pmole/mg protein/min) and 0.25-0.77 pmole/mg protein/min (mean: 0.56 pmole/mg protein/min), respectively. The activities in adenomas and carcinomas associated with Cushing's syndrome were in the range of normal control. The activities in aldosteronomas were significantly higher in 4 cases than those of the normal control and in the range of the normal control in 4 cases, suggesting that the higher activity of 11 beta-hydroxylase is one of the important factors causing mineralocorticoid excess. The activities in adrenocortical carcinomas with AGS were significantly lower, corroborating clinical findings of androgen excess with suppressed production of mineralocorticoid or glucocorticoid. The activities in two cases of nonfunctioning adenomas were in the range of the normal control, but the third case showed higher activity than the normal control. These results show that the abnormal activity of mitochondrial 11 beta-hydroxylase exists in some aldosteronomas, non-functioning adrenocortical adenomas and carcinomas with AGS.