Protein turnover, synthesis and breakdown before and after recovery from protein-energy malnutrition

Abstract

1. Rates of total protein turnover, synthesis and breakdown were measured in five children before and after recovery from severe protein-energy malnutrition and while receiving 0.6 g of protein and 397 kJ day-1 kg-1. 2. Thes rates were calculated after giving doses of [15N]glycine every 2 h along with the feeds and measuring the rate of excretion of [15N]urea in urine. 3. Malnourished children had significantly lower rates of protein turnover, synthesis and breakdown than after they had recovered. 4. During recovery from protein-energy malnutrition, two children on a daily intake of 1.2 g of protein and 605 J/kg body weight, had rates of protein turnover, synthesis and breakdown that were twice as great as those found on admission and higher than after recovery. 5. On the study diet the malnourished children maintained their weight while the recovered children lost weight; the apparent nitrogen balance was more positive in the malnourished children. 6. In recovered children, the rate of protein synthesis was unchanged over a wide range of protein intake, whereas the rate of protein breakdown appeared to rise with a reduction in protein intake.