Qualitative and quantitative changes in uterine mRNA populations in response to oestradiol treatment of rats

The mRNA population of immature rat uteri, responding to different lengths of oestradiol-induced differentiation, have been compared by the technique of DNA hybridization with heterogeneous RNA. Over the first 4 h of hormone induction there are continuing qualitative and quantitative changes in the poly(A)-containing mRNA such that, by 4 h after oestradiol administration, the population bears little resemblance to that of the unstimulated animal. Between 2 h and 4 h after oestradiol administration, the most striking changes appear to be in sequences of intermediate abundance. The possible significance of these findings is discussed.