SEQUENTIAL STIMULATION OF URACIL-RICH AND GUANINE-RICH RNA SPECIES DURING CORTISONE INDUCTION OF HEPATIC ENZYMES

A mixture of 5-3H-uridine and 8-14C-guanine was employed to evaluate hepatic RNA synthesis at various times following a single administration of cortisone. During the first hour of hormone action, which precedes hepatic enzyme induction, uridine-rich RNA was selectively synthesized; subsequently a hormonal stimulation of guanine-rich RNA synthesis occurred. These findings are compatible with early hormonal stimulation of the synthesis of DNA-like RNA (high A+U) followed by synthesis of ribosomal RNA (high G+C). These double-labeled tracer experiments provide some insight into the biochemical processes underlying hormonal enhancement of hepatic enzyme synthesis and the subsequent augumentation of hepatic ribosomal content. © 1969.