Influence of streptozotocin-induced diabetes on the cytoplasmic factors modulating adenylate cyclase activity in rat lungs.

Basal adenylate cyclase activity in rat lung alveolar tissue particulate fraction was depressed during streptozotocin-induced diabetes. However, the activation of the particulate adenylate cyclase by the cytoplasmic factor(s) was markedly increased in lungs from the diabetic rats. The increased activation of basal adenylate cyclase in the diabetic tissue appeared to be due to an increase in the activity of the cytoplasmic factor(s) and not due to an increase in the sensitivity of the particulate enzyme to the cytoplasmic factor(s). Insulin treatment of the diabetic animals restored the activation of adenylate cyclase by the supernatant activator to the control values. The cytoplasmic factor(s) did not appear to be related to the ubiquitous calcium-dependent regulator protein, calmodulin.