THE ULTRAFILTRABLE CALCIUM OF HUMAN SERUM. II. VARIATIONS IN DISEASE STATES AND UNDER EXPERIMENTAL CONDITIONS1

Abstract

The ultrafiltrability of serum Ca in human subjects was determined: (a) in disease states associated with hypercalcemia and (b) before, during and after the parenteral administration of calcium, citrate, phosphate and parathyroid extract. Hypercalcemia from any course led to a proportionate increase in both ultrafiltrable and protein bound Ca so that the percentage of ultrafiltrable Ca was in the normal range. Hypo-calcemia was accompanied by a normal, or more frequently, a high percentage of ultrafiltrable Ca. By the application of physical chemical principles, abnormalities in the concentration of ultrafiltrable Ca in serum have been ascribed to disturbances in the bone: extracellular fluid Ca equilibrium. Abnormalities in the percentage of ultrafiltrable Ca (ratio of ultrafiltrable to total serum Ca) have been related to alterations in calcium-protein interrelationships in serum. In renal disease a specific alteration in the amount of Ca bound to serum proteins appeared to be present.