Characterization and Rapid Labelling of Pituitary RNA

ALTHOUGH there is a great deal of evidence that hormones may directly influence the production of rapidly labelled RNA in many different tissues 1 , some of it is equivocal 2 . Changes in rapidly labelled RNA of rat liver after the administration of hormones have been demonstrated by countercurrent distribution 3 . The interpretation of these changes is by no means clear, but cortisone increased the amount of rapidly labelled RNA in rat liver and pecreased it in rabbit lymphocytes 4 . The pituitary is a source of many hormones, the secretion of which may be influenced by various factors, including the highly specific feed-back effects of the target gland hormones on trophic hormone synthesis. It may then be possible to examine the relationships between hormone action and rapidly labelled RNA production in this gland.