CHAPTER 15 - Protein Metabolism and Requirements in Pregnancy and Lactation

Abstract

This chapter discusses protein metabolism and requirements in pregnancy and lactation. During pregnancy and more especially during lactation, the net rate of protein synthesis by the adult mammal is greatly increased. Lactation implies a rate of synthesis of new protein that is three-to tenfold that noted in pregnancy. However, the rate of synthesis per kilogram of body weight in all species is less in lactation than in early life. The apparent exception of man is largely because of the inclusion of a large term for augmentation of the N content of the tissues of the mother during pregnancy. If the synthesis of pregnancy in women is taken to be the protein deposited in the uterus plus that contributing to the growth of the breast, then the net rate of synthesis is reduced to a third. Net rates of protein synthesis vary appreciably from species to species and on average, the rat synthesizes about 10 times as much protein per unit time per unit body weight as does man, irrespective of whether it is growing, pregnant, or lactating.