RENAL TUBULE NA,K-ATPASE POLARITY IN DIFFERENT ANIMAL-MODELS OF POLYCYSTIC KIDNEY-DISEASE

Apical mislocation of the ubiquitous transport enzyme Na,K-ATPase has been implicated as a feature of cyst development in in vitro studies o f human polycystic kidney disease (PKD) epithelia. We undertook an imm unohistochemical study of murine glucocorticoid-induced PKD, the peg m ouse, the cpk mouse, and the diphenylthiazole (DPT)-induced rat models of PKD to determine if this feature was common to these models of cys t development, Distribution of Na,K-ATPase was determined with a polyc lonal anti-Na,K-ATPase antibody and a nickel-silver-enhanced peroxidas e color development system, Results were documented objectively with d ensitometric techniques, Control animals appropriate to the age, strai n, and species of the experimental groups demonstrated the expected po lar distribution of Na,K-ATPase to the basolateral surface, This distr ibution was more marked in mature animals, Tubular dilatation and cyst ic change, however, were associated with increased apical Na,K-ATPase in all models. The murine models demonstrated decreased basolateral st aining for Na,K-ATPase compared with controls, although this was not a feature of the DPT rat model, Abnormal location of Na,K-ATPase is a s hared feature of a variety of animal models and human PKD. This may co ntribute to abnormal fluid and electrolyte flux favoring cyst formatio n or may represent expression of a less differentiated renal tubule ep ithelial phenotype.