The influence of protein and/or energy deficiency on the growth of long bone in rats.

The effects of protein and/or energy deficiency on long bone growth were studied using rats of an average weight 100g. Four groups of Wistar rats were respectively fed on a normal diet, a low-energy diet, a low protein-diet, and a low-protein and low-energy diet for 45 days. Both energy and protein deficiency restricted gains of body weight and femur length and the activity of alkaline phosphatase in the tibia to the same extent. The epiphyseal growth plates of the femur in protein-deficient rats were as thin as those in energy-deficient rats. On the other hand, femur width and activity of acid phosphatase in the tibia were lower in protein-deficient animals than those in energy-deficient ones. Serum calcium concentrations and calcium content of bone were the same among all groups.