Regulation of Sodium and Water Balance

Three major hormones are involved in regulating sodium and water balance in the body at the level of the kidney.

(1) ADH (antidiuretic hormone) from the posterior pituitary acts on the kidney to promote water reabsorption, thus preventing its loss in the urine.

(2) Aldosterone from the adrenal gland acts on the kidney to promote sodium reabsorption, thus preventing its loss in the urine.

(3) ANH (atrial natriuretic hormone) from the atrium of the heart acts on the kidney to promote sodium excretion so that it is excreted in the urine.