title: Seasonal changes in the plasma isoenzymes of lactate: NADH oxidoreductase in Hereford cows under range conditions.
abstract: Plasma levels of lactate: NADH oxidoreductase (LD) and the proportions of five major isoenzymes were estimated in samples taken in January, March, June, July and November from Hereford cows kept under range conditions. Seasonal changes were observed in both total LD and the proportions of the isoenzymes. Levels of total LD and all isoenzymes were low in winter and high in summer. Proportions of LD4 and LD5, the electrophoretically slow isoenzymes which predominate in muscle, increased in summer at the expense of LD1, the fast isoenzyme which predominates in liver and erythrocytes. LD1 was increased in November, at the time when other isoenzyme levels were decreasing from summer high levels. The seasonal changes observed in plasma LD were attributed to changes in diet and/or water supply and activity of the range cows.
mesh_terms: D000064:Acclimatization; D000818:Animals; D002417:Cattle; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D008099:Liver / Q000201:enzymology; D009132:Muscles / Q000201:enzymology; D012621:Seasons
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase