A model to study the transport function of the intestinal viscera during peritoneal dialysis

A preparation was developed to selectively study the transport properties of the intestinal viscera. A rat was positioned prone on a 100-mL beaker (reservoir) and the viscera were completely immersed and suspended without tension in dialysate solution maintained at 37 degrees C. A volume of 11.6 +/- 0.9 mL was ultrafiltered over a period of 180 minutes with a 5.6% glucose dialysate solution (n = 5) versus 0.5 +/- 0.5 mL for a 1.5% hydrous glucose dialysate solution (n = 4). The suspended viscera were able to absorb glucose from the beaker. The viscera absorbed more glucose when they were suspended in a higher glucose concentration: 922 +/- 46 mg for the 5.6% solution (54% of the initial glucose present) and 151 +/- 13 mg for the 1.5% solution (39% of the initial glucose present). Protein was found to leak from the viscera, and the amount found in dialysate was not related to the concentration of glucose used as dialysate (75 +/- 25 mg for the 5.6% solution and 41 +/- 3 mg for the 1.5% solution; P = NS). Studies also demonstrated transport from blood into the dialysate and that transport into dialysate could be altered by altering visceral blood supply (intravenous infusion of antidiuretic hormone, 800 micrograms/hr). Urea and glucose clearances were greater in the absence of antidiuretic hormone, whereas creatinine and inulin clearances were not different in both groups. This model offers the potential to selectively study the responses of the visceral peritoneum.