Changes in mass of the right ventricle and its RNA content during regression of hypertrophy

Abstract

Noninbred male rats weighing 250–300 g were used. Adaptation to high-altitude hypoxia was produced by keeping the animals once a week for 5 h in a pressure chamber at an “altitude” of 6000 m. The degree of hypertrophy of the right ventricle and its RNA content were studied after 20 days of adaptation and also 2, 10, 20, and 40 days after the end of exposure to hypoxia. The mass of the right ventricle and its RNA concentration and content were significantly increased 20 days after the beginning of adaptation. After the end of exposure to hypoxia half of the increase in mass of the right ventricle was lost during the next 10 days and half of the increase in RNA during the next 2 days. Forty days after the end of exposure to hypoxia the mass of the right ventricle and its RNA content in the adapted animals were indistinguishable from those in the controls.