The effects of catecholamine and related compounds on the adenyl cyclase system in the epidermis*

Abstract

The effect of various hormones and drugs on the adenyl cyclase system of pig and human epidermal slices was studied in vitro. Adrenaline and isoproterenol in the presence of theophylline increased the epidermal cyclic AMP level 20-fold in 5 min. Noradrenaline also stimulated cyclic AMP accumulation but to a much lesser degree. The adrenaline stimulation was marked even in the absence of the phosphodiesterase inhibitor, theophylline. Theophylline potentiated the effect of adrenaline at the concentration of 2–10 mM although theophylline alone did not elevate the cyclic AMP level significantly. The Km for adrenaline stimulation of the adenyl cyclase system of pig epidermis was 77·10⁻⁷ M. A β-adrenergic antagonist, propranolol, markedly inhibited the adrenaline stimulation while α-antagonists, phentolamine or priscoline, showed little effect. These results are in accord with the view that the epidermis possesses an active adenyl cyclase system with β-adrenergic receptors.