[Morphologic and metabolic studies on the effect of ethane-1-hydroxy-1, 1-diphosphonate (EHDP) on the epiphyseal plate and metaphysis of the rat].
Ethane-1-hydroxy-1, 1-diphosphonate (EHDP) has been widely used in recent clinical and laboratory investigations. The author examined epiphyseal and metaphyseal morphology as well as cartilage matrix and calcium metabolism during EHDP administration and after drug discontinuation by 35S, 45Ca and 3H-thymidine autoradiographic study. The effect of low-dose EHDP was limited to osteoclast dysfunction of the metaphysis with resultant widening of trabeculae. High dose administration of EHDP induces a variety of disorders with a manifestation of marked widening of the epiphyseal growth plate. This process is probably derived from a reduction in matrix calcification that relates an inhibition of chondrocyte metabolism with a resultant decreased rate of chondroitin sulfate turnover. Furthermore, high dose EHDP causes a metaphysis which exhibits rickets+-like changes with little calcification and a decrease in the normal rate of osteoprogenitor cell differentiation to osteoblasts and osteocytes.