Effect of protein quality on 14C glucose utilization in isolated rat mammary acini

Poor protein quality has a deleterious effect on lactation in rats. Dams consuming a 13% wheat gluten (WG) diet are unable to maintain litters. Glucose utilization in isolated mammary acini taken from dams at either day 20 of gestation (G20) or day 4 of lactation (L4) was examined in dams consuming 13% WG vs 13% casein-methionine (CM) diets from day of breeding. Dams consuming WG had significantly smaller inguinal-abdominal mammary glands than CM dams at both G20 and L4, and mammary glands of CM but not WG dams were larger at L4 than G20. Both average pup weight and pup daily gain were smaller in WG litters. Basal levels of 14C glucose oxidation (GO) and 14C glucose incorporation into lipid (GL) and lactose were examined. A large significant increase in GO and GL occurred in CM dams from G20 to L4 but not in WG dams. Both GO and GL were higher in CM dams on L4 but not at G20. The ratio of GO:GO+GL changed at parturition in CM but not WG dams. The normal changes in glucose utilization by mammary epithelial cells which occur at parturition were impaired by the WG diet