Nature of RNAs synthesised in rat liver in response to hydrocortisone

Experiments on hybridization of [32P]HnRNA from hydrocortisone-treated rat liver with rat-liver DNA, in competition with unlabelled liver HnRNA from hormone-deficient and treated rats, revealed marked differences in their nucleotide sequence homologies. It was found that the hormone-induced new species of HnRNAs were transcribed both on middle-repetitive and non-repetitive sequences of DNA. However similar differences in the sequence homologies were not detectable in respect of mRNA derived from livers of hydrocortisone-administered and adrenalectomised rats. The results imply that the new species of HnRNA synthesized following hormone treatment may be confined to the nucleus.