Effect of short-term exercise training on angiogenic growth factor gene responses in rats

We investigated whether 1) 5 days of exercise training would reduce the acu te exercise-induced increase in skeletal muscle growth factor gene expressi on; and 2) reductions in the increase in growth factor gene expression in r esponse to short-term exercise training would be coincident with increases in skeletal muscle oxidative potential. Female Wistar rats were used. Six g roups (rest; exercise for 1-5 consecutive days) were used to measure the gr owth factor response through the early phases of an exercise training progr am. Vascular endothelial growth factor (VEGF), transforming growth factor-b eta (1), (TGF-beta (1)), and basic fibroblast growth factor (bFGF) mRNA wer e analyzed from the left gastrocnemius by quantitative Northern blot. Citra te synthase activity was analyzed from the right gastrocnemius. VEGF and TG F-beta, mRNA increased after each of 5 days of exercise training, whereas e xercise on any day did not increase bFGF mRNA. On day 1, the VEGF mRNA resp onse was significantly greater than on days 2-5. However, the reduced incre ase in VEGF mRNA observed on days 2-5 was not coincident with increases in citrate synthase activity. These findings suggest that, in skeletal muscle, 1) VEGF and TGF-beta, mRNA are increased through 5 days of exercise traini ng and 2) the reduced exercise-induced increase in VEGF mRNA responses on d ays 2-5 does not result from increases in oxidative potential.