On the influence of X-ray irradiation and photochemotherapy with 8-methoxypsoralen on the sebaceous gland of the Syrian hamster ear.

30 male Syrian hamsters were X-ray irradiated on 1 ear with 500 rad (Dermopan 2; setting 3; tissue half value thickness, 7.5 mm). 30 other animals were treated locally on one ear with an emulsion containing 0.15% 8-methoxypsoralen and then with UV A (10 treatments in 23 days; total UV A dose, 5.0 J/cm20. The other ear served as control. An in vivo double-labelling autoradiography with 3H- and 14C-thymidine was carried out on half of the animals of each group. The other half was administered 3H-thymidine and the number of labelled cells still in contact with the basal lamina of the sebaceous gland after 6 days was determined. The effects of X-ray irradiation and photochemotherapy are identical. Cell proliferation in the sebaceous gland was reduced, the length of the S phase was shortened, and the number of marked cells still in contact with the basal lamina after 6 days was decreased.