title: Myocardial LDH isoenzyme patterns in rats exposed to cold and/or hypobaric hypoxia.
abstract: Exposure of rats to hypobaric hypoxia (9.5% O2) for 40 days produced cardiac hypertrophy, increases in the total LDH activity and subunit M percentage of LDH and a significant decrease (50%) in H/M ratio when compared to control rats. An equally long exposure to cold (+6 degrees C) did not affect heart weight or total LDH activity, but a significant increase (17.6%) in the H/M ratio developed. Simultaneous exposure to cold (+6 degrees C) and hypoxia (9.5% O2) caused a significant decrease in the H/M ratio, but there was no change in the total LDH-activity when compared to the control group. The poor hypoxic tolerance of the cold-exposed rats could partly be explained by disadvantageous distribution of LDH isoenzymes leading to impaired glycolytic capacity of such an aerobic organ as the heart.
mesh_terms: D000531:Altitude; D000818:Animals; D001835:Body Weight; D006332:Cardiomegaly / Q000209:etiology; D003080:Cold Temperature; D003664:Decompression; D006400:Hematocrit; D000860:Hypoxia / Q000201:enzymology*; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood* / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000473:pathology; D009929:Organ Size; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase