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NaPi-mediated transcellular permeation is the dominant route in intestinal inorganic phosphate absorption in rats.
Drug Metab Pharmacokinet. 2006 Jun; 21(3):217-21.DM

Abstract

Inorganic phosphate in food is absorbed two ways, the transcellular route via the brush border membrane and the paracellular route via tight junctions. NaPi, a sodium-dependent inorganic phosphate transporter, is expressed in rat and human intestine. However, the relative contribution of NaPi to total carrier-mediated transport of physiological concentrations of inorganic phosphate in rat intestine is not clear. Here, we characterized inorganic phosphate transport across the rat small intestine using a voltage-clamp analysis which allowed the diffrentiation of inorganic phosphate permeation through these two (transcellular and paracellular) routes. Results showed that, under a physiologically normal transmucosal electrical potential difference (about 2 mV), permeation of inorganic phosphate by the transcellular route was greater than that by the paracellular route. Further, transport was significantly decreased by the addition to the incubation medium of phosphonoformic acid, a sodium-dependent phosphate transporter inhibitor, and severely inhibited under sodium-free conditions. Similar results were obtained without the voltage-clamp. Together, these results suggest that NaPi-mediated transcellular permeation is the dominant route in the absorption of inorganic phosphate across the small intestine.

Authors+Show Affiliations

Pharmaceutical Research Laboratories, Kirin Brewery Co., Ltd., Gunma, 370-1295, Japan.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16858125

Citation

Eto, Nobuaki, et al. "NaPi-mediated Transcellular Permeation Is the Dominant Route in Intestinal Inorganic Phosphate Absorption in Rats." Drug Metabolism and Pharmacokinetics, vol. 21, no. 3, 2006, pp. 217-21.
Eto N, Tomita M, Hayashi M. NaPi-mediated transcellular permeation is the dominant route in intestinal inorganic phosphate absorption in rats. Drug Metab Pharmacokinet. 2006;21(3):217-21.
Eto, N., Tomita, M., & Hayashi, M. (2006). NaPi-mediated transcellular permeation is the dominant route in intestinal inorganic phosphate absorption in rats. Drug Metabolism and Pharmacokinetics, 21(3), 217-21.
Eto N, Tomita M, Hayashi M. NaPi-mediated Transcellular Permeation Is the Dominant Route in Intestinal Inorganic Phosphate Absorption in Rats. Drug Metab Pharmacokinet. 2006;21(3):217-21. PubMed PMID: 16858125.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - NaPi-mediated transcellular permeation is the dominant route in intestinal inorganic phosphate absorption in rats. AU - Eto,Nobuaki, AU - Tomita,Mikio, AU - Hayashi,Masahiro, PY - 2006/7/22/pubmed PY - 2006/9/27/medline PY - 2006/7/22/entrez SP - 217 EP - 21 JF - Drug metabolism and pharmacokinetics JO - Drug Metab Pharmacokinet VL - 21 IS - 3 N2 - Inorganic phosphate in food is absorbed two ways, the transcellular route via the brush border membrane and the paracellular route via tight junctions. NaPi, a sodium-dependent inorganic phosphate transporter, is expressed in rat and human intestine. However, the relative contribution of NaPi to total carrier-mediated transport of physiological concentrations of inorganic phosphate in rat intestine is not clear. Here, we characterized inorganic phosphate transport across the rat small intestine using a voltage-clamp analysis which allowed the diffrentiation of inorganic phosphate permeation through these two (transcellular and paracellular) routes. Results showed that, under a physiologically normal transmucosal electrical potential difference (about 2 mV), permeation of inorganic phosphate by the transcellular route was greater than that by the paracellular route. Further, transport was significantly decreased by the addition to the incubation medium of phosphonoformic acid, a sodium-dependent phosphate transporter inhibitor, and severely inhibited under sodium-free conditions. Similar results were obtained without the voltage-clamp. Together, these results suggest that NaPi-mediated transcellular permeation is the dominant route in the absorption of inorganic phosphate across the small intestine. SN - 1347-4367 UR - https://www.unboundmedicine.com/medline/citation/16858125/NaPi_mediated_transcellular_permeation_is_the_dominant_route_in_intestinal_inorganic_phosphate_absorption_in_rats_ L2 - http://joi.jlc.jst.go.jp/JST.JSTAGE/dmpk/21.217?from=PubMed DB - PRIME DP - Unbound Medicine ER -