LIVER IS NOT ESSENTIAL FOR SOLUTE TRANSPORT DURING PERITONEAL-DIALYSIS

Based on theoretical calculations on solute exchange capacities of var ious peritoneal tissues, the liver has been predicted to account for u p to 43% of the permeability-surface area product (PS) of the entire p eritoneal ''membrane'' for a small solute (sucrose) during peritoneal dialysis (PD). In these calculations, the abdominal wall and the diaph ragm were found to contribute only similar to 10 to 15% of the total P S. However, evisceration has in previous studies been shown to affect the PS characteristics during PD only marginally (10 to 30%). Ln such evisceration experiments the liver was usually nor removed, and theref ore it has been suggested that an intact liver might have significantl y contributed to the solute exchange under these premises. We assessed the peritoneal PS of Cr-51-EDTA (constantly infused intravenously) an d the plasma-to-peritoneal clearance (Cl-B-->P) of I-125-human serum a lbumin (RISA) (given as an i.v. bolus) in Wistar rats during acute PD. In one group of rats the liver surface was sealed off using Histoacry late glue (N = 6) and in another group a 90% hepatectomy was performed , the remaining portion of the liver, usually the right lower lobe, be ing sealed off by glue (N = 6). A third group was sham operated to ser ve as control (N = 12). The PS for Cr-51-EDTA was 0.32 +/- 0.03( +/- s e) mi min(-1) (N = 12) during control, 0.32 +/- 0.04 ml . min(-1) afte r ''sealing'' of the liver surface (N = 6, P > 0.1) and 0.40 +/- 0.03 after hepatectomy (N = 6, P > 0.1), that is, remained unchanged after experimental intervention. The Cl-B-->P of RISA during control was 5.8 8 +/- 1.0 mu l . min(-1) (N = 10), and was not altered after hepatecto my, 6.17 +/- 0.48 mu l . min(-1) (N = 5 P > 0.1), bur slightly increas ed after liver surface sealing (9.69 +/- 1.09 mu l . min(-1), N = 5, P < 0.05). In conclusion, the present experiments indicate that the liv er does not play an essential role in the overall solute exchange betw een the plasma and the peritoneal cavity (PC) during PD.