Changes in bone and serum minerals after parathyroidectomy and their prevention by portacaval shunt.

The effect of portacaval shunt and parathyroidectomy on the concentration of calcium, magnesium, phosphate and hydroxyproline in the bone and the concentration of the three minerals in the serum has been studied in the growing rat. Parathyroidectomy produced a decreased net bone reabsorption as evidenced by higher concentrations of calcium, magnesium and phosphate; and a reduced net matrix formation, as evidenced by lower concentrations of hydroxyproline. Portacaval shunt, when performed with parathyroidectomy, prevented the development of these changes and produced "normal" concentrations of most of those elements, comparable to their concentrations in the control animals. The changes in serum calcium and magnesium produced by parathyroidectomy were prevented when portacaval shunt was performed in conjunction with the former procedure. Portacaval shunt alone produced no significant changes except for hypophosphatemia. This hypophosphatemia is speculated to have stimulated the production of 1,25-(OH)2D3 in the kidney, which in turn produced those observed effects of portacaval shunt in the parathyroidectomized rat.