Analysis of skeletal development on the basis of body mass and bone resorption

Regression analysis was utilized to define the relationships among body weight, whole skeleton bone resorption (3H-tetracycline method), and the development of skeletal mass. The results indicated that skeletal development (% body weight) of slowly growing, 24-week-old rats consisted of two major components, one directly (r = 0.985, P<0.001) and one inversely (r = 0.977, P<0.001) related to body weight. It was further noted that the skeletal resorption rate was inversely correlated to body weight (r = 0.879, P<0.05) and directly related to skeletal development (r = 0.865, P<0.05), suggesting that whole skeleton bone resorption and formation were highly correlated in the slowly growing animal. A third small component of skeletal development identified in the analysis of data from 24-week-old animals, showed no direct relationship to either body weight or resorptive activity. The model presented enables the separation of skeleton mass into major components which may represent mechanically and metabolically driven bone formation.