The proportion of ribosomes active in protein synthesis and the content of polyribosomal poly(A)-containing RNA in adult and senescent rat livers.

The proportion of ribosomes active in protein synthesis and the content of polyribosomal poly(A)-containing RNA are unchanged when adult and senescent rat livers are compared. Therefore, the decreased protein synthesizing activity of senescent liver microsomes observed previously is not due to a deficiency in total mRNA content.