[Regulation of phosphatemia and hypophosphatemia]

Phosphate is an essential element for cellular metabolism and bone mineralization. The kidney regulates phosphate homeostasis by modulating the proximal reabsorption of phosphate. This regulation is mediated by hormonal or autocrine/paracrine factors. Recent results concerning the molecular structure of phosphate transport systems have clarified the mechanisms underlying the effects of these mediators. Hypophosphatemia is a frequent biological finding which results either from an intracellular shift of phosphate, or from a defect in the intestinal absorption or a renal leak. The decrease in phosphate leads to a depletion in cellular ATP (which accounts for neurological and muscular symptoms), to bone demineralization and to renal lithiasis when a renal leak exists.