Ione Remiao Azzolin

Effect of Protein Malnutrition on Glycoprotein, Protein and Lipid Synthesis in the Rat Cerebellum during the Period of Brain Growth Spurt

Female Wistar rats were fed a normal-protein diet (25% casein) or a low-protein diet (8% casein) during pregnancy and lactation. The two diets were isocaloric and contained appropriate amounts of mineral salts and vitamins. Pups from dams submitted to the low-protein diet had a lower body weight than normally fed controls as early as on the day of birth, but a difference in cerebellar weight between the two groups was observed only on the 15th postnatal day. Malnutrition had no effect on cerebellar protein concentration, which increased with age in both groups. The cerebellar DNA concentration was higher at 7 and 15 days of age in normally fed rats than in malnourished rats, whereas at 21 days of age it was higher in the malnourished animals. [U-14C]Leucine and [2-3H]mannose incorporation into proteins and lipid synthesis from acetyl coenzyme A (CoA) derived from [U-14C]leucine markedly decreased with age in the cerebellum of rats fed both diets. [2-3H]Mannose incorporation into cerebellar glycoproteins was greater in malnourished rats during the period of brain growth spurt than in normally fed rats at all ages studied. Prenatal and postnatal protein malnutrition had no effect on [U-14C]leucine incorporation into cerebellar proteins or on cerebellar lipid synthesis from acetyl-CoA derived from [U-14C]leucine during the period of brain growth spurt.

Effect of Methionine Supplementation to a Low-Soybean Protein Diet on Liver Lipid Metabolism

Female Wistar rats were fed a low-soybean protein (8%) diet supplemented with different concentrations of DL-methionine (0-1.2%) during the lactation period. Diet supplementation with methionine caused a significant increase in rat body weight. The addition of 0.3% DL-methionine to the diet did not cause an increase in liver triacylglycerol concentration in 21-day-old rats, but an increase did occur after the addition of 0.6% DL-methionine to the diet. Supplementation of the diet with DL-methionine did not change liver phospholipid or protein concentrations, nor plasma triacylglycerol levels. Liver lipid synthesis from [1-14C]acetate in 21-day-old rats whose dams had been fed an 8% soybean protein diet supplemented with 1.2% DL-methionine was significantly higher than in the group receiving no DL-methionine supplementation. Hepatic production of CO2 and of water-soluble acid products from [1-14C]palmitate did not differ between groups. Inositol addition to a low-soybean protein diet supplemented with DL-methionine did not change triacylglycerol nor phospholipid levels in the liver.