Plasma-free amino acid response to changes in dietary protein in pregnant and non-pregnant Rhesus monkeys (Macaca mulatta)
The plasma free amino acid response to shortterm dietary isoealoric protein reduction was studied in tour non-pregnant and four pregnant rhesus monkeys (Mariam mulatm). Before the introduction of the protein-reduced diet. a general reduction of most plasma free amino acids was observed during pregnancy compared to the nonpregnant state. The pregnant and non-pregnant monkeys responded differently to the proteinreduced diet, suggesting different mechanisms of
coping with dietary protein restriction. The pregnant monkeys showed a further reduction of Virtually all amino acids while on the protein reduced diet, but normalized these changes after return to the habitual diet. The non-pregnant monkeys showed a decrease in both the essential and non-essential amino acids and an increase in mainly the non~essential amino acids, while on the protein-reduced diet. The decrease was reverted and the increase continued on resumption of the habitual diet. This is probably the pattern of plasma-free amino acid changes that can be expected in primate studies involving both pregnant and non-pregnant Rhesus monkeys using an isocalorie protein-redueed diet.