renal phosphate ion absorption

Definition

Target type: biologicalprocess

A renal system process in which phosphate ions are taken up from the collecting ducts and proximal and distal loops of the nephron. In non-mammalian species, absorption may occur in related structures. [GOC:lb, PMID:18784102, PMID:22506049]

Renal phosphate ion absorption is a complex process that involves the coordinated action of multiple proteins and transporters located in the proximal tubules of the kidneys. The process begins with the filtration of phosphate ions from the blood into the glomerular filtrate. This filtrate then flows through the proximal tubules, where most of the filtered phosphate is reabsorbed back into the bloodstream. This reabsorption is mediated by the sodium-phosphate cotransporter (NaPi-IIa), which is located in the apical membrane of proximal tubule cells. NaPi-IIa utilizes the electrochemical gradient of sodium to drive the uptake of phosphate into the cell. Once inside the cell, phosphate can be transported across the basolateral membrane into the interstitial fluid by several different mechanisms. This movement is driven by the concentration gradient of phosphate between the cell and the interstitial fluid. The activity of NaPi-IIa and other phosphate transporters is regulated by several factors, including: 1) Parathyroid hormone (PTH): PTH inhibits the activity of NaPi-IIa, leading to decreased phosphate reabsorption and increased phosphate excretion. 2) Vitamin D: Vitamin D increases the expression of NaPi-IIa, leading to increased phosphate reabsorption. 3) Dietary phosphate intake: High dietary phosphate intake leads to increased phosphate excretion, whereas low dietary phosphate intake leads to increased phosphate reabsorption. 4) Other hormones and factors: Several other hormones and factors, such as fibroblast growth factor 23 (FGF23), can also influence renal phosphate reabsorption. The reabsorption of phosphate in the kidney plays a crucial role in maintaining phosphate homeostasis in the body. This homeostasis is essential for several vital functions, including bone formation, energy production, and cellular signaling. Disruptions in renal phosphate reabsorption can lead to hypophosphatemia (low blood phosphate levels) or hyperphosphatemia (high blood phosphate levels), which can have serious health consequences. '
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Proteins (1)

Compounds (1)