Familial ADH-responsive diabetes insipidus: response to thiazides and chlorpropamide

Twenty cases of familial ADH-responsive diabetes insipidus were identified within five generations, and eight patients were studied by one of two established dehydration protocols. In each case there was partial to total failure of response to the initial administration of ADH which was slowly corrected by continued administration. This initial failure can lead to misinterpretation of the dehydration test unless the medullary solute washout effect is taken into account in chronically polyuric patients.Treatment consisted of thiazides and/or chlorpropamide. All cases responded well.The response to chlorpropamide suggests that the failure of ADH production is not complete in these patients, and that the major defect is a failure of ADH release in response to normal stimuli. Chlorpropamide may act by either facilitating ADH release or by synergistically interacting with available ADH at the tubular level.