Regulation of vasopressin secretion in a patient with chronic hypernatraemia.
A patient with the chronic hypernatraemia syndrome is described. Using a sensitive and specific radioimmunoassay, the plasma arginine-vasopressin (AVP) level was measured under various conditions. With an unrestricted diet, the plasma AVP level was inappropriately low for the degree of plasma hyperosmolality (0.9 pmol/l and 302 mOsm/kg, respectively). After chronic water loading, plasma osmolality was 271 mOsm/kg, plasma AVP level 1.5 pmol/l, and the urine remained hypertonic with respect to the plasma. During hypertonic saline infusion, plasma osmolality increased from 271 to 294 mOsm/kg without a concomitant increase in the plasma AVP concentration. After sc injection of apomorphine and after haemodynamic stimulation, the plasma AVP concentration increased from 0.8 to 36 pmol/l and from 1.2 to 6.3 pmol/l, respectively. These data demonstrate a selective deficiency in the osmoregulation of the AVP secretion. The observed neuroendocrine abnormalities may be linked to a congenital malformation of the brain.
D000328:Adult; D001058:Apomorphine / Q000494:pharmacology; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000503:physiopathology*; D008297:Male; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D014867:Water / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects
D012462:Saline Solution, Hypertonic; D014867:Water; D001127:Arginine Vasopressin; D001058:Apomorphine