Differential effects of cyclosporine A on ornithine decarboxylase activity induced by ultraviolet-B and PUVA in mouse skin.
The inhibitory effect of cyclosporine A (CsA) on the activity of ornithine decarboxylase (ODC) induced by phorbol ester tumor promoter has been reported. In the present study, the effects of CsA on ODC activity induced by ultraviolet-B (UV-B) and PUVA in the skin of the SKH/hr 1 hairless mouse were investigated. Topical application of CsA (1.7 mumol) to the dorsal skin irradiated with 50 mJ/cm2 UV-B did not remarkably change ODC activity. On the other hand, if CsA was applied simultaneously with 3 J/cm2 UV-A 1 h after treatment with 0.3% 8-methoxypsoralen, PUVA-induced ODC activity was suppressed by about 60% at 12 and 24 h after UV-A irradiation. In the dot blotting analysis of ODC-specific mRNA level, a significant but slight decrease in ODC mRNA level (about 20% inhibition) was observed in the PUVA-treated group compared with the control group (vehicle and UV-A). The inhibition of PUVA-induced ODC activity by CsA may have been caused in part by the decrease in ODC mRNA level and in part by a post-transcriptional regulation mechanism.
Kono
T
T
Department of Dermatology, Osaka City University Medical School, Japan.
Mizuno
N
N
Taniguchi
S
S
Ishii
M
M
Yoshida
H
H
Matsui-Yuasa
I
I
Otani
S
S
Hamada
T
T
D000818:Animals; D003524:Cyclosporins / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D015151:Immunoblotting; D051379:Mice; D008812:Mice, Hairless; D009955:Ornithine Decarboxylase / Q000096:biosynthesis / Q000187:drug effects* / Q000528:radiation effects; D011701:PUVA Therapy; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D014466:Ultraviolet Rays
D003524:Cyclosporins; D012333:RNA, Messenger; D009955:Ornithine Decarboxylase