How to assess transport in animals?

The general principles for assessing solute and fluid transport across the peritoneum in animal models are not different from those in human studies. Animal models allow for extensive standardization of experimental conditions and also for sampling of peritoneal tissues for analysis. The present review will focus on (1) the scaling issue between various species, (2) how to measure intraperitoneal volume in animal models, (3) the impact of an indwelling catheter, (4) the difference between acute and chronic experiments, and (5) the particular problems associated with transport measurements in mice. If done correctly and after proper scaling, mass transfer area coefficients and clearance measurements show marked similarity among different species. Although animal models only partly mimic human peritoneal dialysis, they are valuable tools for understanding the basic physiology and biology of peritoneal dialysis.