Cyclosporin A induced augmentation of the beta-adrenergic adenylate cyclase response of pig epidermis.

It has been known that beta-adrenergic adenylate cyclase response is decreased in psoriatic-involved epidermis. Since the immunosuppressive agent, cyclosporin A, is reported to be effective on psoriasis clinically, the effect of cyclosporin A on beta-adrenergic adenylate cyclase response in pig skin was examined in vitro. Therapeutic serum levels of cyclosporin A (100-400 ng/ml) augmented the beta-adrenergic adenylate cyclase response of the epidermis. Highest levels of cyclosporin A (2-20 micrograms/ml) did not have any effect on its response. Both low Km and high Km cyclic AMP phosphodiesterases were not affected by cyclosporin A. Therefore, it is suggested that the clinical efficacy of cyclosporin A on psoriasis can be explained partially by its direct effect on the keratinocyte itself.