The effects of 4-methyl-2-thiouracil on fibre type and cross-sectional area in the soleus muscle of the rat.
The effects of 4-methyl-2-thiouracil (MTU, 0.1% in drinking water) on the composition and cross-sectional area of muscle fibres of the rat soleus muscle were studied. The percentage of fast twitch-oxidative-glycolytic (FOG) fibres fell after 2 weeks of treatment with MTU to zero at 8 weeks. In contrast the percentage of FOG fibres in untreated animals fell to 19.2 +/- 2.1% during this period. The mean cross-sectional area of FOG and slow twitch-oxidative (SO) fibres were respectively 39.9% and 23.8% smaller than those of their respective controls 6 weeks after treatment. At 8 weeks the percentage reduction of SO fibre area was 26.8% of the control value. This study indicates that MTU treatment causes atrophy and redistribution of fibre type in the soleus muscle.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D006651:Histocytochemistry; D008297:Male; D008779:Methylthiouracil / Q000494:pharmacology*; D009132:Muscles / Q000032:analysis / Q000187:drug effects* / Q000473:pathology; D051381:Rats
D008779:Methylthiouracil