[Plasma levels of beta-endorphin and ACTH and serum levels of cortisol in different stages of arterial hypertension before and after clonidine therapy].

Beta-endorphin (B-Ep), ACTH plasma levels and cortisol serum levels have been evaluated by RIA, in 27 patients suffering from essential blood hypertension and in 20 healthy control subjects. The study was repeated in the hypertensive group after clonidine treatment for 15 days. B-Ep plasma levels were normal in the I stage of hypertension and did not show any significant difference in relation to the severity and duration of hypertension. ACTH and cortisol circulating levels in the hypertensive patients were in normal range. The increase of B-Ep plasma levels in the II and III stage of the hypertension is not modified by the reduction of blood pressure values; therefore it is unlikely linked to the elevated blood pressure, but probably to the vascular complications. Moreover, the results obtained after clonidine treatment seem to exclude that the hypotensive action of the drug is mediated by increment of B-Ep circulating levels.