| Theme |
Hyperphosphatemia |
| Title |
Renal regulation of phosphate handling |
| Author |
Ichiro Ohkido |
Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University, School of Medicine |
| Author |
Akiko Murayama |
Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University, School of Medicine |
| Author |
Takashi Shigematsu |
Division of Nephrology and Hypertension, Department of Internal Medicine, Jikei University, School of Medicine |
| [ Summary ] |
Renal phosphate handling plays a key role in phosphate metabolism, and determines serum phosphate level. Renal dysfunction is major etiology of hyperphos phatemia. Phosphate reabsorption in the renal proximal tubules is mediated by sodium-dependent phosphate (Na/Pi) co transporters. Tmp/GFR prorides good parameters for renal proximal tubular phosphate reabsorption, being better than %TRP. The most important factor on Na/Pi co transporters is parathyroid hormone (PTH). PTH can accelerate urinary phosphate excretion due to an inhibition of phosphate tubular reabsorption with endocytic retrieval of Na/Pi co transporters from the apical membrane. Calcitriol also increases phosphate reabsorption by mediating the expression of the Na/Pi gene. Hyperphosphatemia progress secondary hyperparathyroidism explained by Trade-Off theory in renal failure patients. |