Effect of dibutyryl cyclic-AMP on adrenal catecholamine-synthesizing enzymes in repeatedly immobilized hypophysectomized rats.

Abstract

In hypophysectomized rats, the administration of dibutyryl cyclic-AMP or ACTH results in marked increases in adrenal tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH) and in a small but significant increase in phenylethanolamine-N-methyl transferase (PNMT) levels that parallels the increase in adrenal weight. In repeatedly immobilized hypophysectomized rats, treatment with dibutyryl cyclic-AMP or ACTH results in a marked increase in adrenal DBH and a small but significant increase in adrenal PNMT levels that again parallels the increase in adrenal weight. Levels of adrenal TH in immobilized hypophysectomized rats treated with dibutyryl cyclic-AMP, however, are not greater than levels found in untreated immobilized hypophysectomized rats. ACTH treatment, however, results in restoration of the elevated levels of TH produced by immobilization in normal rats. Dibutyryl cyclic-AMP appears to increase adrenal TH levels through a mechanism similar to that of immobilization (increased splanchnic nerve ac...