Changes in polyribosomes and poly(A)-containing polyribosomal RNA in the uterus of the ovariectomized rat in response to oestradiol-17 beta treatment.

Polyribosome formation and the characteristics of polyribosomal poly(A)-containing RNA from uteri of ovariectomized rats responding to a single dose of oestradiol-17 beta was investigated. The mean proportion of polyribosomes in the atrophic uterus was 65%. In response to 10 micrograms of oestradiol-17 beta/100 g body mass, the amount of polyribosomes increased to 88% 24 h after stimulation. Thereafter the proportion of polyribosomes decreased to a value of 48% at 72h. The pattern of amino acid incorporation in oocytes from Xenopus laevis injected with these polyribosomes was similar to the changes in polyribosome formation and degradation. The polyribosomal poly(A)-containing RNA from the controls consisted of a heterogeneous population of RNA with sedimentation values between 5S and 25S. The hormone stimulation resulted in an increase in both the amount and the size (13S to 35S) of the RNA.