Retinoic acid modulation of ultraviolet light-induced epidermal ornithine decarboxylase activity
Irradiation of skin with ultraviolet light of sunburn range (UVB) leads to a large and rapid induction of the polyamine biosynthetic enzyme ornithine decarboxylase in the epidermis. Induction of epidermal ornithine decarboxylase also occurs following application of the tumor promoting agent 12-0-tetradecanoylphorbol-13 acetate and topical retinoic acid is able to block both this ornithine decarboxylase induction and skin tumor promotion. In the studies described below, topical application of retinoic acid to hairless mouse skin leads to a significant inhibition of UVB-induced epidermal ornithine decarboxylase activity. The degree of this inhibition was dependent on the dose, timing, and frequency of the application of retinoic acid. To show significant inhibition of UVB-induced ornithine decarboxylase the retinoic acid had to be applied within 5 hr of UVB irradiation. If retinoic acid treatment was delayed beyond 7 hr following UVB, then no inhibition of UVB-induced ornithine decarboxylase was observed. The quantities of retinoic acid used (1.7 nmol and 3.4 nmol) have been shown effective at inhibiting 12-0-tetradecanoyl phorbol-13 acetate induced ornithine decarboxylase. The results show that these concentrations of topical retinoic acid applied either before or immediately following UVB irradiation reduces the UVB induction of epidermal ornithine decarboxylase. The effect of retinoic acid in these regimens on UVB-induced skin carcinogenesis is currently under study.
- Research Organization:
- Combined UCLA-V.A. Wadsworth Dermatology Program, Los Angeles, California
- OSTI ID:
- 5474991
- Journal Information:
- J. Invest. Dermatol.; (United States), Vol. 78:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DECARBOXYLASES
INHIBITION
RADIOINDUCTION
ENZYME ACTIVITY
VITAMIN A
RADIOSENSITIVITY EFFECTS
CARCINOGENESIS
FAR ULTRAVIOLET RADIATION
MICE
PHORBOL ESTERS
SKIN
TUMOR PROMOTERS
ANIMALS
BODY
CARBON-CARBON LYASES
CARBOXY-LYASES
CARCINOGENS
ELECTROMAGNETIC RADIATION
ENZYMES
ESTERS
LYASES
MAMMALS
ORGANIC COMPOUNDS
ORGANS
PATHOGENESIS
PROMOTERS
RADIATIONS
RODENTS
ULTRAVIOLET RADIATION
VERTEBRATES
VITAMINS
560152* - Radiation Effects on Animals- Animals