Vasopressin release:  an example of humoral input and humoral output
		• Magnocellular neurons containing vasopressin are sensitive to changes in blood tonicity, releasing more vasopressin upon water loss. Vasopressin increases water resorption in the kidney. • Transecting the neural inputs to the hypothalamus does not disrupt the ability to increase vasopressin release upon water loss. This finding confirms that the signal used by hypothalamic neurons is humoral, and not neural, to modulate vasopressin release.