The effect of ultraviolet radiation and melanocyte-stimulating hormone on tyrosinase activity in epidermal melanocytes of the mouse.
The role of melanocyte stimulating hormone (MSH) as a mediator of the melanogenic response to ultraviolet radiation (UVR) was examined in C57 BL/6 mice. While exposure to UVR (250-300 nm) for 7, 14 and 27 days increased tyrosinase activity in epidermal melanocytes of the ear MSH had no effect and failed to alter the response to UVR. Plasma alpha-MSH concentrations were unchanged following UVR. Theophylline, a phosphodiesterase inhibitor, also had no effect on epidermal tyrosinase activity in non-irradiated and UV irradiated mice. Prostaglandin E2 and arachidonic acid were also ineffective in non-irradiated and UV irradiated mice and indomethacin, an inhibitor of prostaglandin synthesis, failed to increase epidermal tyrosinase activity after UVR. On the other hand, 12-0-tetradecanoyl phorbol 13 acetate, an activator of protein kinase C, increased epidermal tyrosinase activity in non-irradiated mice and also enhanced the effect of UVR.
Seechurn
P
P
Department of Dermatology, University of Newcastle upon Tyne, U.K.
Thody
A J
AJ
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D000078404:Epidermal Cells; D005260:Female; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000097:blood / Q000494:pharmacology*; D008544:Melanocytes / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects*; D051379:Mice; D014442:Monophenol Monooxygenase / Q000378:metabolism* / Q000528:radiation effects; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014466:Ultraviolet Rays
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D009074:Melanocyte-Stimulating Hormones; D013806:Theophylline; D014442:Monophenol Monooxygenase; D011493:Protein Kinase C; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate; D007213:Indomethacin