Effect of ultraviolet irradiation on the activity of rat skin prostaglandin D synthetase.
The effect of ultraviolet light-B (UVB) irradiation on the activity of prostaglandin (PG) D synthetase was investigated in adult rat skin. Rats were irradiated with 500 mJ/cm2 of UVB, and PGD synthetase activity was determined in 100,000 g supernatant of the homogenate of rat skin in the presence of glutathione (GSH) before and 3, 6, 12, and 24 h after irradiation. The PGD synthetase activity was decreased time dependently, and within 24 h after UVB irradiation it had dropped to 50% of the control level before irradiation. In contrast, the synthesizing activities of PGE2 and PGF2 alpha were unaffected by UVB irradiation. The reduction of PGD synthetase activity after UVB irradiation was much more prominent in the epidermis than in the dermis, which was separated by heat treatment (55 degrees C, 30 sec). Immunohistochemical studies, using anti-(rat spleen PGD synthetase) antibody, revealed that the number of immunopositive cells, which were identified as Langerhans cells, decreased in the basal layer of the epidermis 24 h after UVB irradiation. These results, together with the reduction of ATPase positive cells in the epidermis after UVB irradiation, suggest that the decrease of PGD synthetase activity in rat skin by UVB irradiation is, at least in part, due to the reduced Langerhans cell population in the basal layer of the epidermis.
Ikai
K
K
Department of Dermatology, Kyoto University Faculty of Medicine, Japan.
Ujihara
M
M
Kanauchi
H
H
Urade
Y
Y
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D007150:Immunohistochemistry; D007801:Langerhans Cells / Q000201:enzymology; D008297:Male; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011457:Prostaglandins D / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D012867:Skin / Q000166:cytology / Q000201:enzymology* / Q000528:radiation effects; D014466:Ultraviolet Rays
D011457:Prostaglandins D; D011451:Prostaglandin-Endoperoxide Synthases; D000251:Adenosine Triphosphatases