| Abstract: | Progeny of male mice, either irradiated in a single dose of 4.2 Gy prior to mating or intact, were painted with either acetone or acetone solution of 6.15 micrograms 12-0-tetra-decanoylphorbol-13-acetate (TPA) twice a week for 24 weeks from the age of 4 months. The occurrence and number of skin papillomas were registered at 2 and 20 weeks after the final treatment. Painting with acetone was not followed by tumor growth in the progeny of either irradiated or intact mice. At 2 weeks after TPA treatment, the occurrence of skin papillomas in the male and female progeny of unirradiated mice was 21 and 37% whereas at 20 weeks-12 and 15%, respectively. The occurrence of skin papilloma in the irradiated mice progeny at 2 weeks was 75% males and 50% in females whereas at 20 weeks-68 and 43%, respectively. Some F1 progeny of the irradiated male mice were mated prior to TPA treatment, and F2 progeny were treated with either acetone or TPA. In the latter group, the occurrence of skin papilloma at 2 weeks following promotor treatment was 58% for males and 40% for females whereas at 20 weeks--53 and 36%, respectively. The analysis of skin papilloma occurrence by family showed that considering the papilloma-bearing father or mother relationship, the former factor appeared to be responsible for a stronger predisposition to this lesion development in F2 progeny. However, the number of papilloma--bearing animals was the greatest in families where both parents suffered the disease. |
