Decreased accumulation of cyclic adenosine 3',5'-monophosphate in "ischemic" skin after 12-0-tetradecanoyl-phorbol-13-acetate treatment.

The effect of 12-0-tetradecanoyl-phorbol-13-acetate (TPA) on cyclic adenosine 3',5'-monophosphate (cyclic AMP) level in adult mouse skin in response to ischemia was examined. The incubation of skin pieces in a buffered salts medium at 37 degrees C resulted in a rapid accumulation of cyclic AMP. In mouse skin pieces maximum accumulation (about 6 times the basal level) occurred after 2 min incubation and was followed by a rapid decline in the cyclic AMP level. This "ischemic" rise in epidermal cyclic AMP was greatly reduced if skin was used 16 hr after a single application of 17 nmoles of TPA. The effect of TPA on cyclic AMP accumulation in response to ischemia was first observed at 1 hr after TPA treatment and was maximal at 4 hr. The lack of "ischemic" response in TPA-treated skin was not related to an increase in the activity of cyclic AMP phosphodiesterase after TPA application. In addition, the accumulation of cyclic AMP in skin in response to both ischemia and exposure to isoproterenol, adenosine, histamine, or prostaglandin E2 (PGE2) was not observed in skin treated with the tumor promoter TPA.