Anti-diuretic hormone, more commonly known as ADH, is produced by the hypothalamus of the brain, and secreted by the (posterior) pituitary gland. When one has a lesser amount of water in one’s body, more ADH is secreted. This makes the distal convoluted tubule and collecting duct of the nephrons more permeable, allowing more water to be reabsorbed by the body, instead of being lost. When one has an excess of water in one’s body, less ADH is secreted. This results in a decreased permeability of the distal convoluted tubule and collecting duct of the nephrons, allowing less water to be reabsorbed by the body, and hence more water leaves the body, and is excreted in urine. This is important in maintaining a constant internal environment in the body. (Recall: this is what is meant by homeostasis).

Aug 3 2025 - 7:28 PM