Sweat glands decrease their activity, lowering the rate of water loss by perspiration. The smooth muscles contract, decreasing the diameter of the lumen of the blood vessels, which increases resistance and in turn blood pressure. Overhydration or a higher than normal water concentration or blood volume inhibits the osmoreceptors. This inhibition reduces or stops ADH secretion. With a decrease in ADH, the kidneys retain less water, which causes an increase in urine volume output.
Sweat glands increase their activity.
The smooth muscles of the arterioles dilate, reducing resistance and thus lowering blood pressure. In the presence of ADH, the distal convoluted tubule and the collecting ducts become more permeable to water. The ADH molecules bind to the receptor molecules on the cell membranes of the epithelial cells of the distal convoluted tubules and the collecting ducts. Once bound, the cells increase the rate of cyclic AMP synthesis, which increases their permeability to water. Water thus moves out of the tubules and ducts by osmosis into the interstitial spaces.