Comparative investigations on the effect of 5-fluorouracil on the epidermis and the skin appendages.

Groups of 15 guinea pigs and 10 Syrian hamsters were treated with 5-fluorouracil (Fluoro-uracil "Roche") for 8, 22, and 36 days, respectively. 15 guinea pigs and 10 Syrian hamsters remained untreated. At the end of the experiment the hair root status of the guinea pig and the 3H-thymidine labelling index of the sebaceous glands and epidermis on the Syrian hamsters were determined. 5-Fluorouracil leads to a gradual reduction of both the 3H-thymidine labelling index in the epidermis and the sebaceous glands and the amount of anagenetic hair. The effect is slow at the onset, gradually increases, and is still increasing after 3 weeks of treatment. The reduction in the number of labelled cells is significantly larger in the epidermis than the sebaceous glands.