Cyclic AMP-dependent protein kinase activation in hearts from euthyroid and hyperthyroid rats.

The degree of cyclic AMP-dependent protein kinase activation in response to dibutyryl cyclic AMP and norepinephrine was determined in samples of rat heart obtained from hyperthyroid and euthyroid animals. The data indicate that thyroid hormone-induced supersensitivity to the metabolic effects of the catecholamines cannot be explained on the basis of a change in activity of supernatant protein kinase.