Activity of cytochrome c oxidase in the right and left ventricular myocardium of male and female rats exposed to intermittent high altitude hypoxia.

ABSTRACT

The aim of the present study was to compare the capacity of the oxidative metabolism (total activity of cytochrome c oxidase, COX) in the right and left ventricular myocardium of adult rats exposed to intermittent high altitude (IHA) hypoxia simulated in a barochamber (5,000 m, 8 h/day, 5 days/wk, for a total of 32 exposures). In male and female rats, IHA induced significant increases of the right ventricular (RV) weight and protein content, whereas left ventricular (LV) weight and protein content remained unaffected. Consequently, the RV/LV ratio in both sexes markedly increased. Similarly, IHA induced an increase of the total activity of COX in RV in both sexes. The specific activities of COX in homogenate as well as in isolated mitochondria were not changed in IHA-exposed animals, which indicates that the increase of total activity of COX is proportional to the increase of total protein content and RV weight.