心不全患者の運動耐容能と細胞レベルでの乳酸移送蛋白発現量との関連に関する研究

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It has been shown that there are lactate transporter proteins (monocarboxylate transporters : MCT) in the cell membranes of many tissues such as heart, skeletal muscle and red blood cells (RBCs). Seven MCT subtypes have been cloned in recent years. They are specifically distributed among tissues, RBCs, and musde fiber types. Although MCT1 in RBCs can be measured by blood samples, its significance has not been clarified. Firstly we made the polydonal anti-MCT1 antibody by immunizing against rabbits with synthetic peptide (11 amino adds) corresponding to the C-terminal of the human MCT1 molecule. With this antibody we examined the relationship between MCT1 in RBCs and exercise performance. 1) Twelve men (middle or long-distance runners) performed treadmill exercise (with 10% sloop) with stepwise protocol (0.5km/hr/ 3min). The subjects exercised to the point at which blood lactate concentrations were over 4.5 mmol/L; To evaluate exercise performance, we measured running speed at the onset of blood lactate accumulation of 4.0 mmol/L (OBLA). MCT1 in RBCs was measured by blood sample at rest. Results: The speed at the OBIA was 155± 1.3 (km/hr:mean±SD). MCT1 in RBCs was 80.1±41.6 (area density). There was a significant inverse correlation between them (r=-O.73, p<0.01). 2) Eight male student athletes and four Patients with CHF were studied about relationship between MCT andexercise tolerance (peak VO2). Results: There was a significant inverse correlation between MCT and peak V02 as a whole(r=-0.87,p=0.086)Conclusions: The results suggest that MCT1 in RBC play an important role in lactate-transport and might have a great role in determining exercise capacity of both normal persons and patients with CHF.