[Novel phosphate regulating genes and osteoporosis].
The hormones currently believe to influence inorganic phosphate (Pi) metabolism are parathyroid hormone (PTH) and the active metabolite to vitamin D. A new class of phosphate-regulating factors, collectively known as the phosphatonins have been shown to be associated with the hypophosphatemic diseases. The reabsorption of Pi in the kidney is a major determinant of the plasma Pi level. Reabsorption is largely regulated by the type II a sodium-dependent Pi cotransporter (NPT2a) that is expressed in renal proximal tubular cells. Phosphatonins cause Pi wasting by controlling the amount of NPT2a on the apical surface of the proximal tubular cell. A recent finding indicates that mutations in NPT2a can contribute to nephrolithiasis and osteoporosis in humans and suggests that changes in NPT2a levels may also cause other human disease. We discuss the roles of phosphatonins and NPT2a in bone formation.
Miyamoto
Kenichi
K
Department of Molecular Nutrition, Institution of Health Biosciences, The University of Tokushima Graduate School.
Ito
Mikiko
M
Segawa
Hiroko
H
D005966:Glucuronidase; D006801:Humans; D000090265:Klotho Proteins; D008565:Membrane Proteins / Q000235:genetics; D010024:Osteoporosis / Q000235:genetics*; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; D010710:Phosphates / Q000378:metabolism*; D011506:Proteins / Q000235:genetics
D008565:Membrane Proteins; D010710:Phosphates; D011506:Proteins; D005966:Glucuronidase; D000090265:Klotho Proteins; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506231:PHEX protein, human