[Age-dependent avidin induction. V. Changes on the level of post-transcriptional modification].

For the elucidation of the age-dependent reduction of the avidin induction in the ovidict of quails, studies on the level of the post-transcriptional events were performed. In estrogen-treated young animals, the extractable activity of DNA dependent RNA polymerase II increases by 145% after progesterone treatment, while in old animals no increase is observed. In the presence of actinomycin D the incorporation ratio [3H] Ado/[3H] Urd into mRNA increases by about 80% in the case of mature animals; this value is drastically lower (15%) using old animals. The activities of the poly(A)-degrading enzymes in oviducts of mature animals are lower than those in old ones. After progesterone treatment the activities of these enzymes increase in oviducts from old animals, while in young quails no alteration is observed. The possible consequence of these findings on the chain length of the poly(A) segment of mRNA is discussed with regard to its translation capacity.