Nucleic Acid Levels of Rat Anterior Pituitary Glands Following Adrenalectomy.

Abstract

The increased elaboration of a protein hormone of the anterior pituitary gland induced by removal of a target organ may be correlated with alterations in nucleic acid levels reflecting increased protein synthesis. This correlation can be demonstrated in the case of increased adreno-corticotropic hormone (ACTH) production following adrenalectomy. Male rats were adrenalectomized and sacrificed at various times from 2 to 7 days. The anterior pituitary tissue from intact and operated rats was analyzed for ribonucleoprotein (RNA) and desoxyribonucleo-protein (DNA) according to the method of Schneider (''45). Normal rat pituitaries ranged in content from 8-12 [mu]g of RNA and 13-15 [mu]g of DNA/mg of fresh tissue, for an average ratio of RNA/DNA of 0.7. Pituitaries of rats adrenalectomized for 2 days contained 12-18 [mu]g of RNA and 9-11 [mu]g of DNA for an average ratio of 1.5. Nucleic acid contents of animals sacrificed at 3, 5, and 7 days postoperatively were comparable to control levels, and had RNA/DNA ratios of 0.7, 0.9, and 0.8, respectively. The increased RNA level in the pituitary 2 days after adrenalectomy correlates well with the time when glandular ACTH content is rapidly increasing (Gemzell et al. ''51).