Leucine catabolism in mammary tissue, liver and skeletal muscle of dam rat during lactation and weaning
DeSantiago, S.; Torres, N.; Tovar, A.R.
Archives of Medical Research 29(1): 25-32
1998
ISSN/ISBN: 0188-4409 PMID: 9556919 Document Number: 493785
The effect of lactation and weaning on the catabolism of branched-chain amino acids (BCAA) was determined in Sprague-Dawley rats (260+or-20 g, 16 weeks old). Rates of transamination and oxidation of leucine and branched chain alpha -ketoacid dehydrogenase (BCKD) activity were measured in homogenates of mammary gland, skeletal muscle and liver on day 12 of lactation and 24 h after separation of dams from the litter (weaning). Lactating rats consumed 250% more protein than controls. The rate of transamination of [1-14C]leucine by mammary tissue of lactating dams was 6-fold higher than in virgin rats. The rate of transamination remained elevated 4-fold in postweaning rats. Rates of transamination were 3-fold higher in mammary tissue than in muscle of lactating rats. The rate of oxidation of [1-14C] leucine by lactating mammary tissue was 10-fold higher than in control tissue. The capacity of mammary tissue for transamination and oxidation of leucine increased greatly during lactation. It is concluded that the mammary gland may play an important role in the catabolism of BCAA during lactation.