Role of cardiopulmonary mechanoreceptors in ADH release in normal humans.

Although animal studies have shown that cardiopulmonary receptors regulate the release of antidiuretic hormone (ADH), human studies have produced conflicting results. Consequently, we studied 17 normal healthy men to determine the ADH response to selective unloading (decreased stretch) of cardiopulmonary low-pressure receptors by thigh cuff inflation in the supine position. Thigh cuff inflation of 30 to 40 mm Hg decreased the central blood volume and right atrial pressure (cardiopulmonary receptor load), while mean arterial pressure and pulse pressure were unchanged (arterial baroreceptor load). Thigh cuff inflation to this level did not alter plasma osmolality or cardiac output. Plasma ADH increased an average of 67% (p less than 0.01) following thigh cuff inflation compared to the preceding supine baseline. After thigh cuff deflation (n = 6), the ADH decreased toward preinflation values. We conclude that selective unloading of the cardiopulmonary receptors in humans increases plasma ADH levels.