Why does antidiuretic hormone (ADH) secretion rapidly decrease if a dehydrated patient receives an intravenous infusion of hypotonic saline solution, which temporarily lowers plasma osmolality?

💡 Explanation

ADH secretion diminishes when hypotonic saline reduces plasma osmolality because hypothalamic osmoreceptors sense this drop, signaling sufficient hydration. Therefore, ADH release is inhibited to prevent further water reabsorption, rather than baroreceptor pressure changes or other hormonal influences primarily affecting sodium balance.

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