A Creatine Transporter Is Operative at the Brush Border Level of the Rat Jejunal Enterocyte

A Creatine Transporter Is Operative at the Brush Border Level of the Rat Jejunal Enterocyte Although ergogenic effects and health benefits have been reported for creatine used as nutritional supplement, to date little is known about the mechanism of creatine absorption in the small intestine. Thus the current study was undertaken to elucidate the mechanism of creatine intake in rat jejunum with the use of well-purified brush border membrane vesicles, isolated from jejunal enterocyte. Creatine uptake was found markedly stimulated by inwardly directed Na+ and Cl− gradients, potential-sensitive, strongly reduced by the substitution of Na+ and Cl− with various cations and anions and positively affected by intravesicular K+. Moreover, creatine uptake is: 1) significantly inhibited by creatine stuctural analogs, 2) abolished by low concentrations of 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA), 3) saturable as a function of creatine concentration with an apparent Michaelis-Menten constant of 24.08 ± 0.80 μM and a maximal velocity of 391.30 ± 6.19 pmoles mg protein−1 30 s−1. The transport is electrogenic since at least two Na+ and one Cl− are required to transport one creatine molecule. Western blot analysis showed the same amount of creatine transport protein in the jejunal apical membrane when compared to ileum. Thus, these data demonstrate the existence of a Na+- and Cl−-dependent, membrane potential-sensitive, electrogenic carrier-mediated mechanism for creatine absorption in rat jejunal apical membrane vesicles, which is biochemically and pharmacologically similar to those observed in other tissues. However, in other cell types the stimulatory effect of intravesicular K+ was never detected. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

A Creatine Transporter Is Operative at the Brush Border Level of the Rat Jejunal Enterocyte

Loading next page...
 
/lp/springer_journal/a-creatine-transporter-is-operative-at-the-brush-border-level-of-the-1EUCzphoXq
Publisher
Springer-Verlag
Copyright
Copyright © 2004 by Springer-Verlag
Subject
Life Sciences; Human Physiology; Biochemistry, general
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-004-0721-8
Publisher site
See Article on Publisher Site

Abstract

Although ergogenic effects and health benefits have been reported for creatine used as nutritional supplement, to date little is known about the mechanism of creatine absorption in the small intestine. Thus the current study was undertaken to elucidate the mechanism of creatine intake in rat jejunum with the use of well-purified brush border membrane vesicles, isolated from jejunal enterocyte. Creatine uptake was found markedly stimulated by inwardly directed Na+ and Cl− gradients, potential-sensitive, strongly reduced by the substitution of Na+ and Cl− with various cations and anions and positively affected by intravesicular K+. Moreover, creatine uptake is: 1) significantly inhibited by creatine stuctural analogs, 2) abolished by low concentrations of 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA), 3) saturable as a function of creatine concentration with an apparent Michaelis-Menten constant of 24.08 ± 0.80 μM and a maximal velocity of 391.30 ± 6.19 pmoles mg protein−1 30 s−1. The transport is electrogenic since at least two Na+ and one Cl− are required to transport one creatine molecule. Western blot analysis showed the same amount of creatine transport protein in the jejunal apical membrane when compared to ileum. Thus, these data demonstrate the existence of a Na+- and Cl−-dependent, membrane potential-sensitive, electrogenic carrier-mediated mechanism for creatine absorption in rat jejunal apical membrane vesicles, which is biochemically and pharmacologically similar to those observed in other tissues. However, in other cell types the stimulatory effect of intravesicular K+ was never detected.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Jan 1, 2004

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off