Dissociation of Volume and Osmolar Control of ADH in Infancy

It has been amply demonstrated that there are two physiologic stimuli which control the release of antidiuretic hormone (ADH) from the posterior pituitary. The first, delineated by the experiments of E. B. Verney (1947-1948),¹ involves alterations in intracellular volume in "osmoreceptor" cells which are probably in the supraoptic and paraventricular hypothalamic nuclei. The second and more recently defined stimulus appears to involve isotonic changes in some parameter (s) of the extracellular volume.^2-10 While the location of the "volume receptors" is unknown, there is evidence to suggest their locus in the left atrium and adjacent pulmonary venous bed and their communication cephalad via the vagus nerves.^8,11-13

Carter et al¹⁴ have reported a 40-year-old patient with inappropriate secretion of ADH and hyponatremia secondary to head trauma in whom there appeared to be a "dissociation" of osmolar and volume control stimuli. In this patient ADH secretion during the early