Effect of undernutrition on the chemical composition and the activity of alkaline phosphatase in soluble and particulate fractions of the rat calvarium and femur. II: Effect of preweaning undernutrition in the suckling rat.

We studied the effects of undernutrition during the suckling period on the development of the calvarium and the femur of rat pups suckling dams fed a 20% or 5% protein diet. The results show that the maturation of bone is delayed by undernutrition. In both the calvarium and the femur, the particulate fraction alkaline phosphatase reflects the rate increments in calcium and phosphorus uptake in control animals. This association is affected in the undernourished pups, as both the alkaline phosphatase activity in particulate fraction and the calcium and the phosphorus uptake decreased. However, the extent of disturbance was more prominent in the femur than in the calvarium, suggesting that during postnatal undernutrition the calvarium is less affected when compared to prenatal undernutrition, where the femur is less affected. The results from these studies suggest that proper nutrition is necessary for bone development during both the prenatal and postnatal period.