Dietary effects on in vitro rat neuronal protein synthesis during growth and development

In vitro brain neuronal protein synthesis was studied in control and postnatally malnourished newborn rats. The malnourished progeny had, respectively, 20.6% and 72% of the body and brain weights of the controls at 66 days of age. A neuron-enriched fraction (NEF) was separated from rat forebrain. Evaluation of the free leucine pool of the NEF showed decrease with age but no alteration with malnutrition. Protein synthesis was estimated by the rate of in vitro incorporation of 14C-leucine into the TCA-insoluble protein of the NEF in rats at the ages: 1, 7, 14, 21, 28, 35 and 66 days. Protein synthesis in the NEF declined with age in both nutritional states except for a rise to day 14 in the control group. Rates of synthesis declined sharply after 21 days of age reaching an adult level of protein synthesis after about the first month of life in both nutritional states. 14C-leucine incorporation was significantly higher in control over malnourished animals on days 14, 21 and 28.