If excess water is lost through excess sweat and urine, water deficiency occurs in the body. It increases blood density. The news of this change in blood reaches the hypothalamus and the osmoreceptors of the hypothalamus are stimulated. Therefore, antidiuretic hormone (ADH) is produced from the posterior pituitary gland in the process of neurosecretion. ADH increases renal tubular permeability. The renal tubule reabsorbs large amounts of water from the glomerular filtrate and returns it to the blood. It produces less urine and is excreted from the body. This work continues until the water balance in the body.
Again, when the amount of water in the body increases, the blood becomes more fluid. The news of this change in blood reaches the hypothalamus. As a result, the production of antidiuretic hormone (ADH) by the posterior pituitary gland stops or decreases. This causes the renal tubules to become impervious. Renal tubular reabsorption of water from the glomerular filtrate ceases (or is greatly reduced). As a result, more urine is produced and excreted from the body. Urine volume can increase up to 16 ml per minute. This process continues until the water balance in the body.