Levels and distribution of the acid-soluble ribonucleotides in the mammary glands of pregnant and lactating rats

Abstract

The acid-soluble ribonucleotides of rat mammary gland have been measured at different stages of the lactation cycle. There is a general increase of these nucleotides so that the level of the total acid soluble ribonucleotide is raised about 3-fold between late pregnancy and late lactation. All the ribonucleotides appear to participate in this increase and all increase roughly to the same extent. Most of the nucleotides measured showed an abrupt increase at parturition and thereafter increased until about the 15th day of lactation, at which time they reached a plateau value. The pattern of increase appears to be more closely related to the rate of increase of ribonucleic acid in the gland than to the metabolic and synthetic activities of the tissue.