The process of producing large amounts of concentrated urine is called diuresis and the opposite process is called antidiuresis. When the amount of water in the body increases, the blood becomes more liquid. The amount of antidiuretic hormone (ADH) or vasopressin in the blood decreases. Water reabsorption from the glomerular filtrate in the distal convoluted tubule ceases. As a result, the concentration of urine decreases and more urine is produced. It causes frequent and large amounts of urine to be passed out of the body. Low-concentration urine continues to be excreted until the water balance in the body is restored.
Again, dehydration occurs when excess water is lost through excess sweat and urine. It increases blood density. Osmoreceptors of the hypothalamus are stimulated due to this change in blood. Antidiuretic hormone (ADH) production increases. ADH is released into the blood through the posterior pituitary gland in the process of neurosecretion. Water is reabsorbed from the glomerular filtrate by the distal convoluted tubule and returned to the blood. As a result, urine concentration increases and less urine is produced. It results in less number of times and less amount of urine is excreted from the body. More concentrated urine continues to be released until the water balance in the body.