Neuroendocrine regulation of hydromineral homeostasis -- Physiology of vasopressin secretion.-Tubulopathies and alterations of the RAAS -- Familial hyperkalemic hypertension (Gordon Syndrome) -- Diabetes insipidus: Novel diagnostic approaches -- Hydro-saline alterations in central adrenal insufficiency -- Approach to hyponatremia according to the clinical setting.-Electrolyte disturbance in congenital adrenal hyperplasia due to 21-OH deficiency -- Rare forms of congenital adrenal hyperplasia affecting electrolyte homeostasis -- Apparent mineralocorticoid excess (11bHSD2 mutations) -- Aldosterone resistance -- Primary aldosteronism -- From hydro-saline metabolism to metabolic diseases -- Hydro-saline alterations in Cushing disease.