Ornithine decarboxylase activity: control by cyclic nucleotides.

Both exposure to cold and administration of aminophylline result in rapid increases in cyclic adenosine monophosphate (cyclic AMP) in the adrenal medulla and adrenal cortex. These increases are followed by dramatic increases in ornithine decarboxylase activity is due to new enzyme systhesis. The data suggest that the decarboxylase activity is regulated by an increase in cyclic AMP.