TY - JOUR
T1 - Na-dependent D-glucose transport by intestinal brush border membrane vesicles from gilthead sea bream (Sparus aurata)
AU - Sala-Rabanal, M.
AU - Gallardo, M. A.
AU - Sánchez, J.
AU - Planas, J. M.
PY - 2004/11/1
Y1 - 2004/11/1
N2 - Brush border membrane vesicles (BBMV) enriched in sucrase, maltase and alkaline phosphatase, and impoverished in Na+-K+-ATPase, were isolated from proximal and distal intestine of the gilthead sea bream (Sparus aurata) by a MgCl2 precipitation method. Vesicles were suitable for the study of the characteristics of D-glucose apical transport. Only one D-glucose carrier was found in vesicles from each intestinal segment. In both cases, the D-glucose transport system was sodium-dependent, phlorizin-sensitive, significantly inhibited by D-glucose, D-galactose, α-methyl-D-glucose, 3-O-methyl-D-glucose and 2-deoxy-D-glucose, and showed stereospecificity. Apparent affinity constants of D-glucose transport (K t) were 0.24 ± 0.03 mM in proximal and 0.18 ± 0.03 mM in distal intestine. Maximal rate of influx (Jmax) was 47.3 ± 2.2 pmols. mg-1 protein for proximal and 27.3 ± 3.6 pmols. mg -1 protein for distal intestine. Specific phlorizin binding and relative abundance of an anti-SGLT1 reactive protein were significantly higher in proximal than in distal BBMV. These results suggest the presence of the same D-glucose transporter along the intestine, with a higher density in the proximal portion. This transporter is compatible with the sodium-dependent D-glucose carrier described for other fish and with the SGLT1 of higher vertebrates.
AB - Brush border membrane vesicles (BBMV) enriched in sucrase, maltase and alkaline phosphatase, and impoverished in Na+-K+-ATPase, were isolated from proximal and distal intestine of the gilthead sea bream (Sparus aurata) by a MgCl2 precipitation method. Vesicles were suitable for the study of the characteristics of D-glucose apical transport. Only one D-glucose carrier was found in vesicles from each intestinal segment. In both cases, the D-glucose transport system was sodium-dependent, phlorizin-sensitive, significantly inhibited by D-glucose, D-galactose, α-methyl-D-glucose, 3-O-methyl-D-glucose and 2-deoxy-D-glucose, and showed stereospecificity. Apparent affinity constants of D-glucose transport (K t) were 0.24 ± 0.03 mM in proximal and 0.18 ± 0.03 mM in distal intestine. Maximal rate of influx (Jmax) was 47.3 ± 2.2 pmols. mg-1 protein for proximal and 27.3 ± 3.6 pmols. mg -1 protein for distal intestine. Specific phlorizin binding and relative abundance of an anti-SGLT1 reactive protein were significantly higher in proximal than in distal BBMV. These results suggest the presence of the same D-glucose transporter along the intestine, with a higher density in the proximal portion. This transporter is compatible with the sodium-dependent D-glucose carrier described for other fish and with the SGLT1 of higher vertebrates.
KW - Brush border membrane vesicles
KW - Distal intestine
KW - Fish
KW - Freezing
KW - Proximal intestine
KW - SGLT1
UR - http://www.scopus.com/inward/record.url?scp=12544258964&partnerID=8YFLogxK
U2 - 10.1007/s00232-004-0710-y
DO - 10.1007/s00232-004-0710-y
M3 - Article
C2 - 15630546
AN - SCOPUS:12544258964
SN - 0022-2631
VL - 201
SP - 85
EP - 96
JO - Journal of Membrane Biology
JF - Journal of Membrane Biology
IS - 2
ER -