THE RESPONSE OF NORMAL INDIVIDUALS AND PATIENTS WITH DIABETES INSIPIDUS TO THE INGESTION OF WATER 1

Abstract

In normal humans, ingestion of 1200 cc. water is followed by a significant reduction of serum specific conductivity but not by hydremia, as estimated by serum total solids or serum proteins; the point of maximum serum electrolyte dilution precedes the peak of maximum urine flow by about 35 min. This latent period has been interpreted (Verney) as the time required for preformed blood pitressin to fall below its effective antidiuretic level; water diuresis and the polyuria of diabetes insipidus are both attributed to hypopitressinemia. If, however, a large vol. of water is drunk by a diabetes insipidus subject under conditions which should permit an increase in urine flow, no diuresis results for at least 8 hrs. despite the fact that the serum electrolytes have been normally diluted. This capacity of the diabetes insipidus subject to retain extra water is interpreted as evidence that if hypopitressinemia exists it is not the sole defect since, if it were, diuresis should follow water ingestion more promptly than in the normal.