| Abstract: | The content of cyclic nucleotides and the activity of adenylate and guanylate cyclases as well as of cAMP phosphodiesterase in the human hyperplastic adrenals were determined after one- and two-step bilateral adrenalectomy for Itsenko-Cushing's disease. A decrease in cGMP concentration and a corresponding increase in cAMP/cGMP correlation were seen in the 2nd hyperplastic adrenal comparatively to those in the 1st one. An enhanced basal activity of adenylate cyclase and its lowered sensitivity to ACTH were found in the 1st and the 2nd adrenals. These changes correlate with a rise in the blood ACTH concentration in patients after the ablation of one adrenal. It is suggested that the augmented adenylate cyclase activity leads to an increased activation of steroidogenesis enzymes in the rest adrenal, ensuring the elevated rate of corticosteroid secretion. The nature of changes in guanylate cyclase activity is contrary to that of adenylate cyclase; namely, guanylate cyclase basal activity of the 2nd hyperplastic adrenal was shown to be lower than that of the 1st one. The cAMP phosphodiesterase activity in the 1st and the 2nd adrenals remained unchanged. |
