Nitric oxide-related experiments on peritoneal solute transport in the rabbit

Background. It is unclear whether nitric oxide (NO) is important in regulat ing peritoneal transport during non-infected peritoneal dialysis. Methods. In 13 rabbits, 250 mg/l L-arginine, a substrate for NO synthesis w as added to a 3.86% glucose dialysis solution. N-G-monomethyl-L-arginine (L -NMMA) 25 mg/l, an inhibitor of NO synthase, was added to the dialysate in 10 rabbits. Standard peritoneal permeability analyses in rabbits were used to analyse the effects of these interventions on solute transport during 1- h dwells. The addition of 4.5 mg/l nitroprusside to the dialysate in five r abbits was used for validation of this model. Results. Nitroprusside caused an 86% (48-233%) increase in albumin clearanc e, which is similar to the nitroprusside-induced increase found in humans ( 70%). Contrary to human studies, no effect was found on the mass transfer a rea coefficient (MTAC) of urea and creatinine, or on glucose absorption. L- Arginine did not affect either the MTAC of urea and creatinine, or the abso rption of glucose. Peritoneal albumin clearance increased 18% (-24 to 609%) . This resembles the NO-mediated effects of nitroprusside. Addition of L-NM MA caused no change in the solute transport rate. Conclusion. The rabbit dialysis model can be used for analysing the effects of interventions on peritoneal permeability characteristics, although the rabbit peritoneal membrane is probably less sensitive to NO compared with t hat of humans. L-Arginine-induced effects are similar to those of nitroprus side, which suggests that these effects possibly are mediated by NO. As L-N MMA did not affect peritoneal transport, it is unlikely that NO is involved in the regulation of peritoneal permeability in rabbits.