Mechanisms and Regulation of Intestinal Phosphate Absorption

2018 ◽  
pp. 1065-1090 ◽  
Author(s):  
Nati Hernando ◽  
Carsten A. Wagner
Keyword(s):  
Phosphate Absorption ◽  
Intestinal Phosphate Absorption

Regulation by Vitamin D of Intestinal Phosphate Absorption

1980 ◽  
Vol 12 (05) ◽  
pp. 216-219 ◽  
Author(s):  
M. Peterlik ◽  
R. Wasserman
Keyword(s):  
Vitamin D ◽  
Phosphate Absorption ◽  
Intestinal Phosphate Absorption

scholarly journals Combination treatment with tenapanor and sevelamer synergistically reduces urinary phosphorus excretion in rats

2020 ◽  
Author(s):  
Andrew J. King ◽  
Jill Kohler ◽  
Cyra Fung ◽  
Zhengfeng Jiang ◽  
Allison Quach ◽  
...  
Keyword(s):  
Male Rats ◽  
Phosphate Binders ◽  
Phosphate Absorption ◽  
Phosphorus Excretion ◽  
Sevelamer Carbonate ◽  
Sodium Hydrogen Exchanger ◽  
Intestinal Phosphate Absorption ◽  
Urinary Phosphorus Excretion ◽  
Dose Levels ◽  
Nhe3 Inhibitor

The majority of patients with chronic kidney disease (CKD) receiving dialysis do not reach target serum phosphorus concentrations, despite treatment with phosphate binders. Tenapanor is a non-binder, sodium/hydrogen exchanger isoform 3 (NHE3) inhibitor that reduces paracellular intestinal phosphate absorption. This pre-clinical study evaluated the effect of tenapanor and varying doses of sevelamer carbonate on urinary phosphorus excretion, a direct reflection of intestinal phosphate absorption. We measured 24-hour urinary phosphorus excretion in male rats assigned to groups dosed orally with vehicle or tenapanor (0.3 mg/kg/day) and provided a diet containing varying amounts of sevelamer (0-3% w/w). We also evaluated the effect of the addition of tenapanor or vehicle on 24-hour urinary phosphorus excretion to rats on a stable dose of sevelamer (1.5% w/w). When administered together, tenapanor and sevelamer decreased urinary phosphorus excretion significantly more than either tenapanor or sevelamer alone across all sevelamer dose levels. The Bliss statistical model of independence indicated that the combination was synergistic. A stable sevelamer dose (1.5% w/w) reduced mean (±standard error of the mean) urinary phosphorus excretion by 42±3% compared with vehicle; together, tenapanor and sevelamer reduced residual urinary phosphorus excretion by an additional 37±6% (P < 0.05). While both tenapanor and sevelamer reduce intestinal phosphate absorption individually, administration of tenapanor and sevelamer together results in more pronounced reductions in intestinal phosphate absorption than if either agent is administered alone. Further evaluation of combination tenapanor plus phosphate binder treatment in patients receiving dialysis with hyperphosphatemia is warranted.

Aluminum Hydroxide: Evaluation of Two Dosage forms and Two Dosing Schedules in Reducing Intestinal Phosphate Absorption

1978 ◽  
Vol 35 (1) ◽  
pp. 58-61
Author(s):  
Douglas R. Smith ◽  
Bruce S. Chang ◽  
Cary E. Johnson
Keyword(s):  
Aluminum Hydroxide ◽  
Dosage Forms ◽  
Phosphate Absorption ◽  
Intestinal Phosphate Absorption

scholarly journals Significant Species Differences in Intestinal Phosphate Absorption between Dogs, Rats, and Monkeys

2020 ◽  
Vol 66 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Yasuhiro ICHIDA ◽  
Naoto HOSOKAWA ◽  
Ryushi TAKEMOTO ◽  
Takafumi KOIKE ◽  
Tasuku NAKATOGAWA ◽  
...  
Keyword(s):  
Species Differences ◽  
Phosphate Absorption ◽  
Intestinal Phosphate Absorption

L-thyroxine inhibits intestinal phosphate absorption in developing rabbits

1993 ◽  
Vol 13 (11) ◽  
pp. 1283-1293
Author(s):  
Stephen M. Borowitz ◽  
Garth S. Granrud
Keyword(s):  
Phosphate Absorption ◽  
Intestinal Phosphate Absorption

Absorption of Inorganic Phosphate in the Human Small Intestine

1979 ◽  
Vol 56 (5) ◽  
pp. 407-412 ◽  
Author(s):  
J. Walton ◽  
T. K. Gray
Keyword(s):  
Small Intestine ◽  
Inorganic Phosphate ◽  
Water Movement ◽  
Human Subjects ◽  
Sodium Concentration ◽  
Phosphate Concentration ◽  
Phosphate Absorption ◽  
Human Small Intestine ◽  
Intestinal Phosphate Absorption

1. Intestinal phosphate absorption in human subjects was studied by the technique of triple lumen intestinal perfusion in vivo. 2. Ileal phosphate absorption increased as the intraluminal phosphate concentration was increased. 3. Ileal rates of phosphate absorption were lower at any given intraluminal phosphate concentration than previously described jejunal rates. Acidification of the ileal lumen did not increase phosphate absorption. 4. Phosphate absorption was shown in the jejunum to be dependent on the intraluminal sodium concentration. 5. Phosphate absorption in the human small intestine consists of at least two components, one directly proportional to water movement and the second apparently independent of water movement.

Phosphate homeostasis and the renal-gastrointestinal axis

2010 ◽  
Vol 299 (2) ◽  
pp. F285-F296 ◽  
Author(s):  
Joanne Marks ◽  
Edward S. Debnam ◽  
Robert J. Unwin
Keyword(s):  
Small Intestine ◽  
Phosphate Transport ◽  
Phosphate Absorption ◽  
Renal Phosphate Reabsorption ◽  
Sodium Dependent ◽  
Dietary Phosphate ◽  
Intestinal Phosphate Absorption ◽  
End Stage ◽  
And Control ◽  
Renal Phosphate Excretion

Transport of phosphate across intestinal and renal epithelia is essential for normal phosphate balance, yet we know less about the mechanisms and regulation of intestinal phosphate absorption than we do about phosphate handling by the kidney. Recent studies have provided strong evidence that the sodium-phosphate cotransporter NaPi-IIb is responsible for sodium-dependent phosphate absorption by the small intestine, and it might be that this protein can link changes in dietary phosphate to altered renal phosphate excretion to maintain phosphate balance. Evidence is also emerging that specific regions of the small intestine adapt differently to acute or chronic changes in dietary phosphate load and that phosphatonins inhibit both renal and intestinal phosphate transport. This review summarizes our current understanding of the mechanisms and control of intestinal phosphate absorption and how it may be related to renal phosphate reabsorption; it also considers the ways in which the gut could be targeted to prevent, or limit, hyperphosphatemia in chronic and end-stage renal failure.

scholarly journals Tumor necrosis factor-alpha impairs intestinal phosphate absorption in colitis

2009 ◽  
Vol 296 (4) ◽  
pp. G775-G781 ◽  
Author(s):  
Huacong Chen ◽  
Hua Xu ◽  
Jiali Dong ◽  
Jing Li ◽  
Fayez K. Ghishan
Keyword(s):  
Egf Receptor ◽  
Phosphate Transport ◽  
Luciferase Assay ◽  
Receptor Interaction ◽  
Mobility Shift ◽  
Necrosis Factor Alpha ◽  
Bone Disorders ◽  
Phosphate Absorption ◽  
Tnf Α ◽  
Intestinal Phosphate Absorption

Phosphate homeostasis is critical for many physiological functions. Up to 85% of phosphate is stored in bone and teeth. The remaining 15% is distributed in cells. Phosphate absorption across the brush-border membrane (BBM) of enterocytes occurs mainly via a sodium-dependent pathway, which is mediated by type IIb sodium-phosphate cotransporters (NaPi-IIb). Patients of inflammatory bowel diseases (IBDs) suffer not only from diarrhea and nutrient malabsorption but also from bone loss. About 31–59% of patients with IBD develop bone disorders. Since the intestine is a primary location for dietary phosphate absorption, it is logical to postulate that there is an inverse relationship between gastrointestinal disorders and phosphate transport, which, in turn, contributes to bone disorders observed in patients with IBD. Phosphate absorption and NaPi-IIb expression was studied with BBM vesicles isolated from trinitrobenzene sulphonic acid (TNBS) animals as well as in Caco-2 cells. The mechanism of TNF-α downregulation of NaPi-IIb expression was investigated by luciferase assay, gel mobility shift assay (GMSA), and coimmunoprecipitation. Intestinal phosphate absorption mediated by NaPi-IIb was reduced both in TNBS colitis and in TNF-α-treated cells. Transient transfection indicated that TNF-α inhibits NaPi-IIb expression by reducing NaPi-IIb basal promoter activity. GMSAs identified NF1 protein as an important factor in TNF-α-mediated NaPi-IIb downregulation. Signaling transduction study and coimmunoprecipitation suggested that TNF-α interacts with EGF receptor to activate ERK1/2 pathway. Intestinal phosphate absorption mediated by NaPi-IIb protein is reduced in colitis. This inhibition is mediated by the proinflammatory cytokine TNF-α through a novel molecular mechanism involving TNF-α/EGF receptor interaction.

Calcitonin Inhibition of Intestinal Phosphate Absorption

1973 ◽  
Vol 242 (120) ◽  
pp. 221-222 ◽  
Author(s):  
F. S. TÄNZER ◽  
J. M. NAVIA
Keyword(s):  
Phosphate Absorption ◽  
Intestinal Phosphate Absorption
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