Lactate transport in rat adipocytes: identification of monocarboxylate transporter 1 (MCT1) and its modulation during streptozotocin-induced diabetes.
We have characterised L-lactate transport in rat adipocytes and determined whether these cells express a carrier belonging to the monocarboxylate transporter family. L-Lactate was taken up by adipocytes in a time-dependent, non-saturable manner and was inhibited (by approximately 90%) by alpha-cyano-4-hydroxycinnamate. Lactate transport was stimulated by 3.7-fold upon lowering extracellular pH from 7.5 to 6.5 suggesting the presence of a lactate/proton-cotransporter. Antibodies against mono carboxylate transporter 1 (MCT1) reacted positively with plasma membranes (PM), but not with intracellular membranes, prepared from adipocytes. MCTI expression was down-regulated in PM of adipocytes from diabetic rats, which also displayed a corresponding loss (approximately 64%) in their capacity to transport lactate. The data support a role for MCT1 in lactate transport and suggest that changes in MCT1 expression are likely to have important implications for adipocyte lactate metabolism.
Hajduch
E
E
Department of Anatomy and Physiology, University of Dundee, UK.
Heyes
R R
RR
Watt
P W
PW
Hundal
H S
HS
D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003373:Coumaric Acids / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D051275:Glucose Transporter Type 4; D051296:Glucose Transporter Type 5; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000378:metabolism*; D019344:Lactic Acid / Q000493:pharmacokinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D027501:Monocarboxylic Acid Transporters; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis; D009124:Muscle Proteins; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D002352:Carrier Proteins; D003373:Coumaric Acids; D051275:Glucose Transporter Type 4; D051296:Glucose Transporter Type 5; D007773:Lactates; D027501:Monocarboxylic Acid Transporters; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; C007175:alpha-cyano-4-hydroxycinnamate; D019344:Lactic Acid