Effect of food restriction on lactate sarcolemmal transport.

The objective of this study was to investigate the effects of 6 weeks of food restriction (FR) on sarcolemmal lactate transport in rats. The daily food consumption of rats was monitored for 10 days, after which they were assigned to either a control group (CTL, n = 7) that consumed food ad libitum or an FR group (n = 7) that received a daily ration equal to 60% of their predetermined baseline food intake. After the 6-week period, we observed in red gastrocnemius (RG) a fall of 48% in glycogen content (P <.01) and a reduction in glutathione peroxidase activity (P <.05), confirming that the FR program was well executed. FR resulted in a reduction in muscle lactate (P <.05) and liver glycogen contents (P <.01). Moreover, hyperlactatemia was noted in the FR group: 1.77 +/- 0.24 versus 2.67 +/- 0.29 mmol/L (P <.05). Lactate transport capacity was significantly increased (P <.05) in FR rats, although monocarboxylate transporter isoforms (MCT1 and MCT4) did not change significantly. We conclude that FR alters sarcolemmal lactate transport activity without affecting MCT1 and MCT4 expression. Copyright 2003, Elsevier Science (USA). All rights reserved.