ALANINE AMINOTRANSFERASE ACTIVITY IN MAMMARY TISSUE, MUSCLE AND LIVEROF DAM RAT DURING LACTATION AND WEANING

Transamination reaction is the first step in the catabolism of most of the L-amino acids, Alanine is an important molecule in the inter-orga n nitrogen transport, conveying them from muscle to the liver, Amino g roups from this amino acid are generally first transferred to a-ketogl utarate in the cytosol of liver cells to form glutamate and leaving be hind the corresponding a-keto acid analog. Measurements of the alanine aminotransferase (EC 2.6.1.2.) activity were compared in liver, mamma ry gland and skeletal muscle in virgin, lactating and weaning dam rats ,In this study liver was the principal tissue involved in alanine tran samination, while muscle showed a reduction in the enzyme activity dur ing lactation, Results indicate an increase in alanine aminotransferas e activity in the mammary gland during lactation and weaning when comp ared with virgin rats. This suggests that mammary gland during lactati on is an important extra-hepatic tissue involved in the metabolism of alanine and probably shunted into the pathways for amino group metabol ism in terms of nitrogen economy.