Metabolic adaptation of myocardial mitochondria to mild altitude hypoxia.

We studied the metabolic parameters of myocardial mitochondria (respiration, respiratory control index, oxidative phosphorylation rapidity and coefficient of oxidative phosphorylation) in two groups of rats: one living at an altitude of 140 m above sea level (control group) and the other living from birth at an altitude of 1350 m above sea level for 2 and 4 months (experimental group). Compared with the control rats, the experimental rats during 2 and 4 months of mild altitude acclimatization increased their basal and stimulated respiration, as well as the rapidity of energy production by myocardial mitochondria. The coefficient of oxidative phosphorylation under mild altitude hypoxia decreased but the respiratory control index did not change.

Protective effect of oestradiol on the heart of rats exposed to acute ischaemia.

Sex-related differences in mortality from ischaemic heart disease are attributed chiefly to difference in the incidence of atherosclerosis. Little attention has been paid to the influence of sex hormones on resistance of the myocardium itself to acute ischaemia. Experiments on rats showed that isolated female hearts were more resistant than male hearts.

Age-dependent influence of a moderate altitude (1,350 m) on the rat cardiopulmonary system.

The aim of the study was to determine whether a moderate altitude (1,350 m, Strbské Pleso, High Tatras) would act as a hypoxic stimulus on the cardiopulmonary system of young and adult rats. We used three experimental groups of animals differing in the duration of time for which they were kept at the given altitude (60 and 120 days) and the age at which they were acclimatized (from the 5th and the 60th day of life). The controls were kept at an altitude of 200 m (Prague).