EFFECT OF PROGESTERONE ON RNA AND PROTEIN SYNTHESIS IN THE RAT UTERUS

The effect of gestagenic compounds on the oestrogen induced nucleic acid and protein synthesis of the rat uterus after castration was investigated. Progesterone causes an inhibition of 3H-uridine incorporation into uterine RNA. The inhibitory effect is strongest when progesterone is administered within 1 hour before isotope labelling. Evaluation of the free labelled nucleotides shows that this effect is not achieved by a blockade of permeability at the cell membrane or by reduction of the phosphorylation process. As a result of this progesterone-induced inhibition, protein synthesis is also reduced. These results are discussed with regard to the modifying effect of progesterone on oestrogen dependent functions in the uterus.