Increased N-Acetyltaurine in the Skeletal Muscle After Endurance Exercise in Rat.

Taurine is metabolized to a novel metabolite, N-acetyltaurine (NAT), through N-acetylation with acetate. Furthermore, NAT production increases when the endogenous production of acetate is elevated in some situations, such as alcohol catabolism and endurance exercise. We have previously reported that both the serum concentration and urinary excretion of NAT from humans were increased after endurance exercise, and that NAT was secreted by cultured skeletal muscle cells exposed to both acetate and taurine. The present study evaluated the hypothesis that NAT is synthesized in the skeletal muscle after endurance exercise. Normal rats were loaded to a transient treadmill running until exhaustion. Serum, skeletal muscle, and liver were collected immediately after the exercise. The NAT concentration in the plasma and in the soleus muscle from the exercised rats was significantly increased compared to that in the samples from the sedentary control rats. There was a significant positive correlation in the NAT concentration between the plasma and soleus muscle. The NAT concentration in the liver was unchanged after the endurance exercise. These results confirm that the significantly increased NAT in both the serum and urine after endurance exercise is derived from NAT synthesis in the skeletal muscle.