Long chain fatty acid uptake by human intestinal mucosa in vitro: mechanisms of transport.
OBJECTIVE
The aim of this study was to investigate whether a carrier-mediated membrane transport for long chain fatty acid (LCFA) exists in the human intestinal mucosa.


METHODS
Biopsies obtained from the small intestine of patients, during routine endoscopies, were incubated for different periods in the presence of [(3)H]oleic acid complexed to albumin, and lipid fractions were separated and quantified. Biopsies were also incubated during 5 min in different oleic acid:albumin molar ratios. The effect of temperature on lipid transport was tested by incubating biopsies at 37 and 4 degrees C.


RESULTS
Maximum [(3)H]oleic acid uptake occurred at 15 min. With increasing unbound oleic acid concentrations in the medium, LCFA uptake during 5 min of incubation revealed a typical saturation kinetics profile, and exhibiting apparent K(m) values of 3.43 +/- 0.83 microM, and apparent V(max) values of 0.86 +/- 0.07 nmol x min(-1) x mg(-1). Within this period, nearly all intracellular fatty acid remained in the unesterified form. The system was also temperature-dependent, having shown a significant reduction of 78.03% in [(3)H]oleic acid uptake at 4 degrees C, in 5 min of incubation.


CONCLUSIONS
Our data confirm that LCFA uptake by human intestinal mucosa is likely to occur via a saturable carrier.
Chaves
Célia Regina M
CR
University Hospital Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Brazil.
Elias
Paulo Roberto P
PR
Cheng
Wanli
W
Zaltman
Cyrla
C
Iglesias
Antônio Carlos R
AC
Braulio
Valeria B
VB
D000328:Adult; D001693:Biological Transport, Active / Q000502:physiology; D004386:Duodenum; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019301:Oleic Acid / Q000378:metabolism*
D019301:Oleic Acid