Renal and endocrine regulation of water and electrolyte balance.

The kidneys have primary responsibility for regulating the body's water and solute balance. Of the 180 L per day that are filtered at the glomerulus, about 98 to 99 per cent is reabsorbed throughout the course of the renal tubule. The kidney can produce a concentrated urine or a dilute urine, depending on the needs of the body. Several hormones, notably aldosterone, ADH, PTH, and calcitonin, as well as vitamin D, are important in the regulation of water and solutes. This article has not discussed other important renal functions as noted in the introduction.