EFFECT OF DRUGS ON PERITONEAL DIALYSIS IN THE DOG

¹ Departments of Pharmacology and Physiology, Dartmouth Medical School, Hanover, New Hampshire

The rates of migration of potassium and iodide ions during peritoneal dialysis in dogs can be modified by adding drugs and enzymes to the dialysis fluid. Net fluxes of potassium diffusing from blood into the peritoneal cavity and of I¹³¹-iodide moving in the opposite direction have been expressed in terms of dialysance. The addition of hyaluronidase and papain caused no significant change in the dialysance of either solute. Vasopressin significantly decreased the values for both potassium and iodide, the fractional decrement being greater for the latter. In contrast, the constants for both ions increased significantly when streptokinase was added to the dialysis fluid. Serotonin also increased the constants for both ions, but significantly so only for potassium.

As a measure of the rate of solute exchange between blood and peritoneal fluid, the dialysance might be altered by any drug that influences splanchnic blood flow or the permeability of the interposed membranes, or both. The present results suggest that vasopressin in dialysis fluid decreased splanchnic blood flow and also altered the permeability of the dialyzing membranes. The results with streptokinase and serotonin are best explained by increases in permeability of one or more diffusion barriers between peritoneal cavity and blood.