The effect of oophorectomy on the ribonucleic acid metabolism of a transplantable uterine tumour.

1. The incorporation of [(14)C]phenylalanine and of [(3)H]uridine into the Guerin T8 uterine carcinoma has been examined. 2. The addition in vitro of polyuridylic acid caused an increase in the incorporation of labelled phenylalanine into tumour microsomes obtained from both oophorectomized and intact animals. 3. Oophorectomy of tumour-bearing animals decreased the specific activity due to the uptake in vivo of [(3)H]uridine into both the soluble and insoluble RNA of the tumour. 4. Actinomycin D caused a decrease in specific activity of RNA in the tumour in vivo, and puromycin inhibited uptake in vitro into tumour microsomes.