Effect of hypothalamic extracts on protein synthesis in rat anterior pituitary tissue.

Abstract

Summary1. Evidence obtained by radio-autography and sucrose density gradient centrifugation indicated that macromolecular RNA was synthesized in explants of rat anterior pituitary tissue in vitro. 2. The rapidly labeled RNA was, in part, heavier than 28S. 3. After 4 hours of incubation, label was observed in cytoplasmic ribosomal RNA. 4. The rate of RNA synthesis in glands treated with hypothalamic or cerebral cortex extracts in vitro was found to be similar. 5. The decreased rate of RNA synthesis in pituitaries treated with hypothalamic extracts in vitro (vs. corresponding controls treated with 0.1 N HCl) could be partially overcome by preincubating the glands in radioactive Medium 199 prior to addition of the extracts. 6. The in vitro rates of RNA synthesis in pituitaries taken from animals previously injected with hypothalamic extracts or 0.1 N HCl were similar, although an initial lag in uptake of uridine-H3 into the glands of the experimental group was observed.