Sulphur Amino Acid Levels in Some Tissues of the Rat during Pregnancy and Lactation

Abstract

Variations in free sulphur amino acid content in some rat tissues have been measured during pregnancy and lactation. As a general trend, sulphur amino acids tend to accumulate in tissues in late pregnancy. This accumulation is quantitatively more important in the liver and striated muscle than in the skin and the kidneys. Among sulphur amino acids, taurine shows the most marked changes, with a maximum accumulation in the liver and striated muscle in day 19 of pregnancy. After delivery, the levels of amino acids in the tissue pools show a tendency to drop, especially in liver and striated muscle. As expected, taurine shows the most marked decrease, returning to normal values in muscle but decreasing to depletion in the liver on day 20 after delivery. These results can be interpreted as follows: during pregnancy, increased food intake is sufficient to accomodate the metabolic needs of the mother, but during lactation, the requirements of milk synthesis promote the release of these amino acids from the tissues.