title: Metabolic type of muscles of the sheep. III. evolution with age and influence of sex.
abstract: Myofibrillar ATPase activity (in the presence of Ca2+ and Mg2+), activities of various glycolytic and mitochondrial enzymes, and haemin iron, glycogen, ATP and lactic acid levels were determined in the heart and five skeletal muscles of the sheep as a function of age and sex. During growth from 2 to 13 months, ATPase activity remained stable whereas most mitochondrial and glycolytic activities tended to decrease, particularly between 2 and 6 months. The isoenzyme composition of lactic dehydrogenase evolved markedly, with in particular a rise in the percentage of M4. Haemin iron level rose from 6 months. These modifications occurred in most of the skeletal muscles but rarely in the heart. Glycogen and ATP decreased progressively between 2 and 13 months. Overall, results indicated a regression of the metabolic differentiation among muscles between 2 and 13 months, particularly marked before 6 months. At 3 and 7 months, sex had practically no influence on the enzyme activities studied.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D005075:Biological Evolution; D005260:Female; D006019:Glycolysis; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D012737:Sex Factors; D012756:Sheep / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D000251:Adenosine Triphosphatases