Effect of adrenalectomy and insulin insufficiency upon the adenosine 3', 5' cyclic monophosphate system of the rat mammary glands.

Effects of adrenalectomy and acute insulin insufficiency upon tissue adenosine 3', 5' cyclic monophosphate concentrations, and adenyl cyclase, phosphodiesterase, and protein kinase activities were investigated. Adrenalectomy decreased intracellular adenosine 3', 5' cyclic monophosphate 53% and increased the activities of both adenylcyclase and phosphodiesterase. Cortisol therapy returned these to normal. During insulin insufficiency caused by anti-insulin serum, mammary adenosine 3', 5' cyclic monophosphate concentrations increased. The acute effects of insulin insufficiency and chronic effects of adrenelectomy suggest that insulin acts upon rat mammary glands to decrease and glucocorticoids, acting over longer term, to increase adenosine 3', 5' cyclic monophosphate concentrations.