EFFECT OF PREGNANCY AND LACTATION ON GLYCOSYLTRANSFERASE ACTIVITIES OF RAT MAMMARY-GLAND

1. 1. Effect of stage of pregnancy and lactation on levels of protein. DNA, lactose synthetase. CMP-N-acetylneuraminic acid synthetase, CMP-N-acetylneuraminic acid: GM3 sialyltransferase. CMP-N-acetylneuraminic acid: GM, sialyltransferase. and UDP-galactose:glucosyl ceramide galactosyltransferase in rat mammary gland were examined. 2. 2. In all cases protein content and enzyme activities began to increase one to 2 weeks before parturition and demonstrated sharp increases one to three days after parturition. 3. 3. Maximum enzyme activity, expressed per unit protein, occurred around day thirteen of lactation for all enzymes examined except for CMP-N-acetylneuraminic acid: GM3 sialyltransferase. 4. 4. There was a strong positive correlation between the levels of lactose synthetase. CMP-N-acetylneuraminic acid synthetase. CMP-N-acetylneuraminic acid: GM1 sialyltransferase and UDP-galactose:glucosyl ceramide galactosyl-transferase on any given day. 5. 5. Analysis of variance demonstrated that enzyme levels showed linear, quadratic and cubic properties over the course of the experimental period. © 1979.