Influences of thyroid hormones on the activity levels of glycogen phosphorylase, hexokinase, triosephosphate dehydrogenase, citrate synthase, 3-hydroxyacyl-CoA dehydrogenase, mitochondrial glycerolphosphate dehydrogenase and the content of cytochrome u3 were examined in a "white" (m. rectus fernoris), "red" (m. soleus) and heart muscle of male rats. Of the enzymes examined, glycerolphosphate dehydrogenase and hexokinase, revealed most significant increases, with comparable extent and simultaneous time of onset. The pattern of reaction was, however, different in the three types of muscle. I n white muscle, an increase of hexokinase, but not of glycerolphosphate dehydrogenase was found. I n red muscle, the two enzymes increased in parallel and in heart muscle the increase in glycerolphosphate dehydrogenase was the largest and exceeded by far that of hexokinase. In skeletal muscles it could be shown that the increase of hexokinase activity was limited to hexokinase-isoenzyme 11, hexokinase I being unaffected.Histochemical staining for glycerolphosphate dehydrogenase revealed that the activity of this enzyme is predominantly demonstrable in the subsarcolemmal mitochondria. The increased activities of hexokinase in the skeletal muscles and of glycerolphosphate dehydrogenase in red and heart muscle are interpreted as a coordinate process of a "long-term metabolic regulation" which is related to an elevated aerobic carbohydrate catabolism of muscle tissue and to an enhanced rate of basal metabolism. studied several glycolytic enzymes and found that hexokinase is one of the more strongly induced enzymes. Krause and Wollenberger [ 101 examined enzymes involved in glycogen metabolism and found increased activities of glycogen phosphorylase, phosphorylase kinase and glycogen synthetase. These various results, however, are not easy to compare, since mode of application and dosage of the hormones were different and the measurements were performed in muscles which were not well defined and may have been heterogeneous in composition of "white" and "red" fibres. As was shown in previous communications (for references see [i l]), marked differences exist between the enzyme activity patterns of energy-supplying metabolism in white and red muscle. It wits therefore the purpose of this study to compare muscles of different metabolic type (white, red and heart muscle [11-16]) with regard to their response to increased levels of thyroid hormones. Activities of enzymes were examined which in previous studies had been shown to represent definite metabolic systems and to indicate by their ratios certain metabolic correlations.

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No phosphagen is present in the body-wall muscle of Ascaris lumbricoides. A stable phosphorus compound, which on the basis of its chemical reactions seems to be 1,2-proepanediol-2-phosphate, constitutes more than half of the acid-soluble phosphorus compounds.

No abstract

No phosphagen is present in the body-wall muscle of Ascaris lumbricoides . A stable phosphorus compound, which on the basis of its chemical reactions seems to be 1,2-propanediol-2-phosphate, constitutes more than half of the acid-soluble phosphorus compounds.