Blood amino acid compartmentalization during pregnancy and lactation in the rat

The blood amino acid compartmentalization during pregnancy and lactation of the rat have been studied. Cellular amino acid levels are similar to those of the plasmatic fraction. Important generalized decreases are detected on days 12 and 21 of the pregnancy; Glu + Gln, Ala and essential and semiessential amino acids being the most affected. During lactation, after a transient phase on day 1 after delivery, there is a generalized increase in blood levels, especially in the plasma fraction, that affects the whole essential values. The different patterns shown by amino acids during pregnancy and lactation confirm that the measurement of plasmatic levels underestimates the actual capacity of whole blood to transport amino acids.