Close association of accelerated rates of whole body protein turnover (synthesis and breakdown) and energy expenditure in children with newly diagnosed acute lymphocytic leukemia.

Using a single-dose [15N]glycine turnover technique, we studied protein metabolism in 15 children with newly diagnosed acute lymphocytic leukemia (ALL). As in our previous study, we observed increased rates of whole body protein synthesis (S) and breakdown (B) in comparison to healthy controls. In eight patients, we assessed basal metabolic rate (BMR). There was a significant linear regression between BMR (kcal/d) (Y) and S (g protein/d) (X): y = 3.7 X + 850 (R = 0.925, p less than 0.001). There was also a significant linear correlation between BMR, expressed as a percentage of the normal value, and S expressed as a percentage of the mean value in the healthy children (r = 0.79, p less than 0.05). There were also significant positive correlations between BMR and body weight (r = 0.75, p less than 0.05) or age (r = 0.83, p less than 0.05) and between S and weight or age (both, r = 0.86, p less than 0.01). BMR (kcal/d) also correlated with B (g protein/d) (r = 0.91, p less than 0.01). Multiple regression analysis revealed that BMR was much more highly related to S than to weight. These data suggest that increased rates of S are closely related to increased energy requirements in patients with ALL. Furthermore, these data provide evidence for the biological relevance of whole body protein kinetics.