Figure 2.

Enzyme activities of respiratory complexes I (CI) and IV (CIV) in isolated cardiac mitochondria of left ventricles. Male and female fetuses were exposed to normoxia (NMX, circles) and early-onset [25 days (25d) gestation, 39d duration] and late-onset (50d gestation, 14d duration) hypoxia (HPX, triangles). Activity rates were measured in tissues obtained at term (64d gestation) as oxidation rates of substrate per minute per milligram mitochondrial protein (CI: oxidation of NADH; CIV: oxidation of ferricytochrome c). *Significant differences at P < 0.05 vs. NMX controls; n = 7 or 8 animals in each group.