THE ROLE OF THE KIDNEY IN THE PARATHYROID CONTROL OF THE BLOOD CALCIUM AS DETERMINED BY STUDIES ON THE NEPHRECTOMIZED DOG

Abstract

The hypocalcemia and tetany which followed parathyroidectomy were effectively controlled by the intraperitoneal injection of an electrolyte solution having the composition of an ultrafiltrate of blood enriched with Ca. Following nephrectomy of the thyroparathyroidectomized dog the blood Ca declined and tetany developed as in the animal with intact kidneys. The nephrectomized dog also responded by an increase in serum Ca level to the injection of parathyroid hormone. This response gradually diminished during the days following nephrectomy, but occurred even some weeks following nephrectomy if the animal was maintained by intermittent peritoneal lavage. It is concluded that the parathyroid hormone exerts its effect on blood Ca by its direct action on the bones rather than through any action on the kidney. The peritoneal membrane may be used as an in vivo membrane for, determining the degree of binding of blood constituents. When studied by this method Ca and Mg were found to be bound to a considerable degree but inorganic phosphate, even at high levels, appeared to be almost entirely filterable.