Salt, water, and vasopressin in polycystic kidney disease.

Excessive salt intake and vasopressin may promote cyst growth in autosomal dominant polycystic kidney disease and glomerular filtration rate (GFR) decline in chronic kidney disease. Kramers et al. confirmed the effects of salt in a large autosomal dominant polycystic kidney disease cohort. Copeptin mediated 72% and 25% of the salt effects on GFR decline and kidney growth. Kidney growth did not significantly contribute to the copeptin-mediated salt effect on GFR. Differences in kidney growth and GFR decline trajectories and factors other than cyst growth contributing to GFR decline may explain the divergent effects.