| Abstract: | It has been reported that hydrocortisone had a protective effect on beta-adrenergic adenylate cyclase system of the pig epidermis during in vitro long term incubation. Using the same experimental system, the effects of another glucocorticoid, betamethasone 17 valerate were investigated. In short term experiments (5 min incubation time), betamethasone had no effect on the cyclic AMP accumulation of the epidermis. When skin slices were incubated with this compound for 48 hours, the response of the skin to epinephrine was preserved and showed a greater accumulation of cyclic AMP in betamethasone-treated skin than in the control. This effect was observed at concentrations greater than 0.001 μM of betamethasone, with the maximal accumulation of cyclic AMP at 0.1 μM. Neither histamine responsiveness nor cyclic AMP phosphodiesterase activities (low and high Km enzymes) were altered by the betamethasone treatment. Thus, betamethasone showed a protective effect against the beta-adrenergic adenylate cyclase system similar to that of hydrocortisone in much lower concentrations. These effects of glucocorticoids would be the essential pharmacological action of this type of hormone on epidermis, and glucocorticoids might reveal their biological activity through the cyclic AMP system of the skin. |
