Comparison of the effects of age and phorbol myristate acetate on the β-adrenergic system in mouse epidermis

The β-adrenergic hormone responsiveness of mouse epidermis exhibited an age-dependent decrease. The 3–4-fold loss of response to isoproterenol was seen between 3 and 6 months of age, and the response remained at a depressed level through 18 months of age. No differences were seen between either the number or binding affinities of epidermal β-receptors in 2- and 12-month-old animals. The skin tumor promoter, phorbol myristate acetate, inhibited the β-adrenergic response independently of age.