[Adenyl cyclase activity and the stimulation of adenosine 3',5'-cyclic monophosphate in blood vessel walls during ageing and under stress (author's transl)].

It is well-known that the cAMP-adenylate cyclase system is important in mediating the effects of numerous hormones. We investigated the age-dependent behaviour of this system in aortas and femoral arteries of male Wistar rats (at the age of 10 days, 1, 4, 8, 12, and 22 months). It was found that: The basic adenylate cyclase activity had considerably been decreased beyond the first month of life, thereafter it was almost constant. The response of adenylate cyclase to guanylyl-imidodi-phosphate and NaF had essentially been elevated since the 4th month of age. The possibility of stimulating the cAMP generation due to epinephrine and histamine had substantially been increased since the 12th month of age. Besides the ability of adrenaline and histamine to stimulate the formation of cyclic AMP was investigated in broken cell preparation and intact cells of smooth muscle of the aorta and femoral artery of rats which had been subjected to daily intermittend immobilization of 1, 3, and 17 weeks. It was found that this type of stress led to an instability of the blood pressure which was associated with an increase in the sensitivity of adenylate cyclase in the broken cell preparations from the arteries to adrenaline and histamine and with a heightened cyclic AMP response to the two hormones in the intact arterial smooth muscle cells. The sensitivity of cardiac adenylate cyclase for adrenaline remained unchanged.