[Changes in the activity of adenylate- and guanylate cyclase in different rat tissues after chronic administration of ACTH or cortisol].

The state of adenylate and guanylate cyclases in the adrenals, suprarenal fat and ventricular myocardium of the rat was studied under conditions of chronic administration of ACTH or cortisol. By the end of ACTH injections the weight of the adrenals and the DNA content in them increased 6 and 3 times, respectively; both parameters showed a gradual increase. The corticosteroid level in the blood changed throughout the experiment.

[Dynamics of adenylate cyclase desensitization during long-term exposure to the hormone].

The dependence of adrenal gland adenylate cyclase desensitization on the dose of in vivo injected ACTH, the time of occurrence and duration of the enzyme refractory period and the dependence of desensitization on the number of ACTH injections were analyzed. The experiments were carried out on guinea pigs injected with prolonged action preparations of ACTH (4 and 6 units) daily for 1-6 days. Intramuscular injections of ACTH caused adenylate cyclase refraction to the repeated action of the hormone.

[The role of periodic changes in cyclase and protein kinase activity in the mechanism of the proliferative effect of ACTH].

A prolonged effect of ACTH on the state of adenylate and guanylate cyclase systems in the adrenal glands of experimental animals was investigated. It was found that in guinea pigs injected with ACTH (4 units daily for 1-50 days) the weight of adrenal glands and the DNA content in these organs increased 2.0-2.

[Species and organ differences in the activity and regulation of adenylate and guanylate cyclases].

The activity of adenylate and guanylate cyclases was determined in adrenal, heart, liver and fat tissues of guinea pigs, mice, rabbits and monkeys. The enzymes activities varied markedly depending both on the species and organs. The highest basal activities of adenylate cyclase was observed in all organs of guinea pigs.

[Adenylate- and guanylate cyclase systems in pathology of the adrenal glands].

The authors have summed up the results of a study of the activity of adenylate and guanylate cyclase system in the adrenals of patients with the Icenko-Cushing disease and syndrome and in the adrenals of experimental animals after unilateral adrenalectomy and in ACTH administration. It has been established that the biochemical mechanisms of compensatory hypertrophy of the adrenals in the normal and pathological tissue differ significantly. It has been shown for the first time that an increase in the basal activity of adenylate cyclase, resulting in the restoration of the initial hormonal level, is an obligatory condition for the compensation of organ function.