title: Effect of phorbol ester application and other mitogenic treatments on 3',5'-cyclic-nucleotide phosphodiesterase activity in mouse epidermis in vivo.
abstract: The effects of phorbol ester application and of other mitogenic treatments on the activity of 3',5'-cyclic-nucleotide phosphodiesterase were investigated in dorsal mouse epidermis in vivo. Local treatment with either the weak tumor promoter phorbol 12,13-dibenzoate or the strong promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) increased the activity of the high affinity enzyme (Km = 4 microM). The enzymic changes began within the first hour after application, and lasted for about 5 days. maximal stimulations of approximately 300--400% were reached after 3--6 h with TPA application, whereas with phorbol dibenzoate the maximum could only be reached after 1--2 days. TPA stimulation of the enzyme depended on doses within the range of 0.2 to 20 nmol and could be completely prevented by cycloheximide, but not by 5-azacytidine, actinomycin D, 5,8,11,14-eicosatetraynoic acid or indomethacin. No evidence could be found for cAMP participation in enzyme induction. An increase in enzyme activity could also be observed after other mitogenic treatments such as local application of the weakly promoting phorbol esters C14:4-phorbol acetate ("Ti8") and 4.O-methyl-TPA, or of the non-promoting divalent cation ionophore A 23187, as well as after treatment with a depilatory cream. Skin massage or removal of the horny layer, which also stimulate mitosis, did not evoke a significant increase in enzyme activity. No apparent correlation exists between the hyperplasiogenic and tumor-promoting effectiveness of a manipulation and its effect on epidermal 3',5'-cyclic-nucleotide phosphodiesterase.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004817:Epidermis / Q000187:drug effects / Q000201:enzymology; D005260:Female; D006965:Hyperplasia; D051379:Mice; D008938:Mitosis / Q000187:drug effects; D009369:Neoplasms / Q000139:chemically induced; D010703:Phorbol Esters / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects / Q000201:enzymology*; D013329:Structure-Activity Relationship
chemical_list: D010703:Phorbol Esters; D010704:Phorbols; D000001:Calcimycin; D015105:3',5'-Cyclic-AMP Phosphodiesterases