Mechanism of ammonium transport: Inhibition by potassium and barium

Michael Koch, M. C. Hall

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Elucidating the precise mechanism of intestinal ammonium transport is critical to the understanding of the acidosis associated with intestinal urinary diversion. Unfortunately, it is incompletely understood and controversial. Recently, we have shown that furosemide and Ba2+ significantly inhibit ammonium absorption in the ileum. On the basis of this and other data, we have suggested that ionized ammonium absorption occurs via K+-transport pathways. The present study examines intestinal ammonium absorption and its inhibition by K+ and Ba2+ utilizing a simplified in vivo system in rat distal ileum. Ammonium absorption demonstrates a tendency towards saturation at initial concentrations between 0 and 300 mM/l. Above 300 mM/l. there was a marked increase in ammonium absorption suggesting a possible biological effect of high NH4+ concentrations on the intestinal segment. Potassium inhibits ammonium absorption. K+ (50 mM/l.) significantly inhibited ammonium at an initial concentration of 100 mM/l. (p + (100 mM/l.) inhibited ammonium absorption at both 50 and 100 mM/l. (p + inhibition occurs via a competitive mechanism. Ba2+ (25 mM/l.) was shown to be a potent inhibitor of ammonium absorption. This significant inhibition persisted at high initial ammonium concentrations suggesting a complex, noncompetitive mechanism of inhibition. In conclusion, this study provides important data further suggesting that ammonium transport in the intestine occurs via K+ transport pathways, and suggests that the traditionally held mechanism of nonionic ammonium diffusion needs reevaluation.

Original languageEnglish (US)
Pages (from-to)1285-1287
Number of pages3
JournalJournal of Urology
Volume148
Issue number4
StatePublished - 1992
Externally publishedYes

Fingerprint

Barium
Ammonium Compounds
Potassium
Ileum
Urinary Diversion
Intestinal Absorption
Furosemide
Acidosis
Intestines

Keywords

  • ammonium compounds
  • intestines
  • urinary diversion

ASJC Scopus subject areas

  • Urology

Cite this

Mechanism of ammonium transport : Inhibition by potassium and barium. / Koch, Michael; Hall, M. C.

In: Journal of Urology, Vol. 148, No. 4, 1992, p. 1285-1287.

Research output: Contribution to journalArticle

@article{93a0f30d53fe444782e447b96609ba30,
title = "Mechanism of ammonium transport: Inhibition by potassium and barium",
abstract = "Elucidating the precise mechanism of intestinal ammonium transport is critical to the understanding of the acidosis associated with intestinal urinary diversion. Unfortunately, it is incompletely understood and controversial. Recently, we have shown that furosemide and Ba2+ significantly inhibit ammonium absorption in the ileum. On the basis of this and other data, we have suggested that ionized ammonium absorption occurs via K+-transport pathways. The present study examines intestinal ammonium absorption and its inhibition by K+ and Ba2+ utilizing a simplified in vivo system in rat distal ileum. Ammonium absorption demonstrates a tendency towards saturation at initial concentrations between 0 and 300 mM/l. Above 300 mM/l. there was a marked increase in ammonium absorption suggesting a possible biological effect of high NH4+ concentrations on the intestinal segment. Potassium inhibits ammonium absorption. K+ (50 mM/l.) significantly inhibited ammonium at an initial concentration of 100 mM/l. (p + (100 mM/l.) inhibited ammonium absorption at both 50 and 100 mM/l. (p + inhibition occurs via a competitive mechanism. Ba2+ (25 mM/l.) was shown to be a potent inhibitor of ammonium absorption. This significant inhibition persisted at high initial ammonium concentrations suggesting a complex, noncompetitive mechanism of inhibition. In conclusion, this study provides important data further suggesting that ammonium transport in the intestine occurs via K+ transport pathways, and suggests that the traditionally held mechanism of nonionic ammonium diffusion needs reevaluation.",
keywords = "ammonium compounds, intestines, urinary diversion",
author = "Michael Koch and Hall, {M. C.}",
year = "1992",
language = "English (US)",
volume = "148",
pages = "1285--1287",
journal = "Journal of Urology",
issn = "0022-5347",
publisher = "Elsevier Inc.",
number = "4",

}

TY - JOUR

T1 - Mechanism of ammonium transport

T2 - Inhibition by potassium and barium

AU - Koch, Michael

AU - Hall, M. C.

PY - 1992

Y1 - 1992

N2 - Elucidating the precise mechanism of intestinal ammonium transport is critical to the understanding of the acidosis associated with intestinal urinary diversion. Unfortunately, it is incompletely understood and controversial. Recently, we have shown that furosemide and Ba2+ significantly inhibit ammonium absorption in the ileum. On the basis of this and other data, we have suggested that ionized ammonium absorption occurs via K+-transport pathways. The present study examines intestinal ammonium absorption and its inhibition by K+ and Ba2+ utilizing a simplified in vivo system in rat distal ileum. Ammonium absorption demonstrates a tendency towards saturation at initial concentrations between 0 and 300 mM/l. Above 300 mM/l. there was a marked increase in ammonium absorption suggesting a possible biological effect of high NH4+ concentrations on the intestinal segment. Potassium inhibits ammonium absorption. K+ (50 mM/l.) significantly inhibited ammonium at an initial concentration of 100 mM/l. (p + (100 mM/l.) inhibited ammonium absorption at both 50 and 100 mM/l. (p + inhibition occurs via a competitive mechanism. Ba2+ (25 mM/l.) was shown to be a potent inhibitor of ammonium absorption. This significant inhibition persisted at high initial ammonium concentrations suggesting a complex, noncompetitive mechanism of inhibition. In conclusion, this study provides important data further suggesting that ammonium transport in the intestine occurs via K+ transport pathways, and suggests that the traditionally held mechanism of nonionic ammonium diffusion needs reevaluation.

AB - Elucidating the precise mechanism of intestinal ammonium transport is critical to the understanding of the acidosis associated with intestinal urinary diversion. Unfortunately, it is incompletely understood and controversial. Recently, we have shown that furosemide and Ba2+ significantly inhibit ammonium absorption in the ileum. On the basis of this and other data, we have suggested that ionized ammonium absorption occurs via K+-transport pathways. The present study examines intestinal ammonium absorption and its inhibition by K+ and Ba2+ utilizing a simplified in vivo system in rat distal ileum. Ammonium absorption demonstrates a tendency towards saturation at initial concentrations between 0 and 300 mM/l. Above 300 mM/l. there was a marked increase in ammonium absorption suggesting a possible biological effect of high NH4+ concentrations on the intestinal segment. Potassium inhibits ammonium absorption. K+ (50 mM/l.) significantly inhibited ammonium at an initial concentration of 100 mM/l. (p + (100 mM/l.) inhibited ammonium absorption at both 50 and 100 mM/l. (p + inhibition occurs via a competitive mechanism. Ba2+ (25 mM/l.) was shown to be a potent inhibitor of ammonium absorption. This significant inhibition persisted at high initial ammonium concentrations suggesting a complex, noncompetitive mechanism of inhibition. In conclusion, this study provides important data further suggesting that ammonium transport in the intestine occurs via K+ transport pathways, and suggests that the traditionally held mechanism of nonionic ammonium diffusion needs reevaluation.

KW - ammonium compounds

KW - intestines

KW - urinary diversion

UR - http://www.scopus.com/inward/record.url?scp=0026744176&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0026744176&partnerID=8YFLogxK

M3 - Article

C2 - 1404661

AN - SCOPUS:0026744176

VL - 148

SP - 1285

EP - 1287

JO - Journal of Urology

JF - Journal of Urology

SN - 0022-5347

IS - 4

ER -