Abstract
Thiamin metabolism in red (soleus, S) and white (extensor digitorum longus, EDL) muscles was characterized. Thiamin triphosphate (TTP) was present at high concentration in EDL muscle from various animals except for mouse. TTP in the muscle was localized in soluble fraction as a protein-unbound form, whereas that in brain was only in particulate fraction. Particulate TTPase in the muscle was stimulated by nitrate anion, while the brain enzyme was not. The content of thiamin diphosphate (TDP) and activities of 2-oxoglutarate dehydrogenase, transketolase and thiamin pyrophosphokinase were higher in rat S muscle than in EDL, whereas TTP level was less in the former than in the later. The difference between the two muscle in thiamin metabolism except TTP level disappeared after denervation, but not after tenotomy. TDP-dependent enzyme activities, thiamin metabolism-related enzyme activities and thiamin phosphate levels were almost the same in rat EDL and S muscles at 2 weeks of age. The difference in thiamin metabolism between the two muscles was observed after 3 weeks of age.
