Coupled diminished energy turnover and phosphorylase a formation in contracting hypothyroid rat muscle.
Hypothyroidism leads to a diminished phosphorylase a formation and a reduction in both glycogen breakdown and lactate production during tetanic stimulation of fast-twitch skeletal muscle (mixed type). Phosphorylase kinase activity is almost 50% lower in the hypothyroid (Tx) group, and the possibility that this might explain the reduction in phosphorylase a formation is discussed. In both the Tx group and the euthyroid (C) group the reconversion of phosphorylase a to b correlates well with a decrease in the energy cost for contraction.
D000818:Animals; D004734:Energy Metabolism; D007037:Hypothyroidism / Q000201:enzymology / Q000378:metabolism*; D007773:Lactates / Q000096:biosynthesis; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000201:enzymology / Q000378:metabolism*; D010764:Phosphorylase Kinase / Q000378:metabolism; D010765:Phosphorylase Phosphatase / Q000378:metabolism; D010762:Phosphorylase a / Q000096:biosynthesis*; D006005:Phosphorylases / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains
D007773:Lactates; D010762:Phosphorylase a; D006005:Phosphorylases; D010764:Phosphorylase Kinase; D010765:Phosphorylase Phosphatase