Central Diabetes Insipidus

The study aims to investigate whether intranasal oxytocin (OXT) improves sexual well-being in patients with Arginine Vasopressin Deficiency (AVP-D). The trial consists of two parts: Part A assesses the effect of OXT on sexual well-being and intimacy over a 7-day treatment period in participants in a stable partnership. Part B assesses the effect of a single dose OXT on sexual arousal, fear and empathy in a clinical setting and is designed for single participants and those in partnerships.

The investigator hypothesize that low-dose MDMA (3,4-methylenedioxymethamphetamine) will produce a sufficiently strong oxytocin stimulation in healthy controls and no relevant increase in patients. This study will confirm previously published data and provide important safety data with low-dose MDMA stimulation testing.

The exploration of polyuro-polydipsia syndrome (PPS) with hypotonic polyuria should distinguished, primary polydipsia (PP) due to excessive water intake, central diabetes insipidus (CDI) related to insufficient secretion of antidiuretic hormone (AVP), and nephrogenic diabetes insipidus (NDI) related to AVP insensitivity. The determination of plasma AVP is not relevant (unstable concentration, short in vitro half-life, long technical time and large blood sample). The differential diagnosis is currently based on a water deprivation test (WDT), an indirect reflection of AVP action, requiring more than 6 hours of hospitalization with risk of dehydration and low accuracy. Copeptin represents a new biomarker, direct mirror of AVP release with remarkable characteristics (stable, rapid determination, small blood volume). Copeptin has become a diagnostic tool in adult PPS and eliminated WDT in the diagnostic process. In children, basal copeptin values help for NDI and to exclude CDI (basal copeptin threshold \> 30 and \> 3.53 pmol/l (Se 100%, Sp 87.4%), respectively). Below 3.53 pmol/l, basal copeptin performance was inadequate to discriminate PP and CDI, highlighting the relevance of the stimulated copeptin study to improve this strategy. The arginine stimulation test is widely used as a simple, short duration (2 hours) and well tolerated tool to diagnose growth hormone deficiency in pediatrics. The performance of this test for copeptin stimulation was studied in adults with PPS with a high diagnostic accuracy. The aim of the study is identify the best discriminant threshold of the arginine stimulation test in the uncertain diagnosis (basal copeptin \<30 pmol/l) in the polyuro-polydipsic syndrome in children. Then evaluate the discriminative capacities of the arginine stimulation test between the primary polydipsia and central insipid diabetes in the polyuro-polydipsic syndrome in children. And finally evaluate the cost-effectiveness of a new decisional algorithm for the differential diagnosis of PPS in children and evaluate the impact of infusion volume on copeptin secretion using the protidemia copeptin ratio.