GRN and diabetes insipidus: To dissect out the underlying cause, which may be clinically relevant for progranulin-deficient patients, we assessed drinking and feeding behavior, metabolic functions, plasma vasopressin and other neuropeptides, morphology of the kidney and hypothalamus and aquaporins in aged progranulin deficient and control mice, and in summary, the data reveal a renal water loss without glucosuria with high vasopressin suggesting a nephrogenic diabetes insipidus.