Mannitol-induced Release of Copeptin in Healthy Adults and Patients With Polyuria-Polydipsia Syndrome (MARS Study)

Inclusion Criteria: Part 1: Proof of Concept in Healthy adults * Age ≥ 18 years * Healthy with no medication except hormonal contraception Part 2: Pilot Study in Patients with primary polydipsia (PP) or arginine vasopressin deficiency (AVP-D) * Age ≥ 18 years * Evidence of polyuria \> 40-50 ml/kg body weight per 24 hours and polydipsia \> 3 Liter per 24 hours or regular desmopressin medication corresponding to a diagnosis of PP or AVP-D Exclusion Criteria: Part 1: Proof of Concept in Healthy adults * Participation in a trial with investigational drugs within 30 days * Evidence of disordered drinking habits and diuresis defined as polyuria \> 40-50 ml/kg body weight per 24 hours and polydipsia \> 3 Liter per 24 hours. * Estimated Glomerular Filtration Rate (eGFR) \< 60 ml/min/1,73 m2 * Glucose \> 11.1 mmol/L corresponding to the diagnosis of an uncontrolled diabetes mellitus * History of urinary tract obstruction * Problems with urination * Pregnancy or breastfeeding * Multiple allergies (≥ 3) * Evidence of acute illness Part 2: Pilot Study in Patients with PP or AVP-D * Participation in a trial with investigational drugs within 30 days * Pregnancy or breastfeeding * Evidence of acute illness * eGFR \< 60 ml/min/1,73 m2 * Glucose \> 11.1 mmol/L corresponding to the diagnosis of uncontrolled diabetes mellitus * History of urinary tract obstruction * Problems with urination * Therapy with diuretics * Multiple allergies (≥ 3)