Heavy chains of striated muscles myosins in NMRI mice on hypocaloric diet

Halleux, G. Maréchal, Georges [UCL] Godfraind-De Becker, A. [UCL]

Male NMRI mice 60 days old were submitted to a hypocaloric diet consisting in a 40% restriction of the mean spontaneous intake. They lost about 15% weight in 7-10 d; animals used for a longer term experimental (49 d) stabilized their weight. The myosin heavy chains (MHC) were separated by gel electrophoresis (SDS-PAGE 5%) and the proportion of the different MHC's was determined by densitometry of the gels. In extensor digitorum longus (EDL, a fast muscle) the proportion of MHC2A increased after 9 d caloric restriction and that the difference is still more apparent after 49 d. There is a slight non-significant increase of MHC2A in soleus, a slow muscle. Hypocaloric diet slows down markedly fast muscles (EDL) and moderately slow muscles (Soleus).