Prenatal Cu intake by rat dams is the principle determinant of cardiac cytochrome c oxidase activity in their offspring.

Preceding studies have shown that cardiac cytochrome c oxidase (CCO) deficiency occurs in the offspring of Cu-deficient rats on postnatal days (PND) 15 and 21. In order to determine if the CCO deficiency resulted from low prenatal Cu intake rather than from low postnatal Cu intake, pups from dams fed AIN93G diet containing 1 mg Cu/kg (CuD dams) were cross fostered to dams fed diet containing 6 mg Cu/kg (CuA dams) and vice versa on PND 1. Pups that remained with their birth dams served as controls. All dams began dietary treatment with either CuD or CuA diets 3 weeks before conception and remained on their respective diets until PND 21. On PND 21, CCO activities (U/mg protein, mean±SEM) in isolated cardiac mitochondria were 3.25±0.06 in pups of CuA dams (N=26), 3.30±0.11 in pups of CuA dams cross fostered to CuD dams (N=8), 2.52±0.10 in pups of CuD dams cross fostered to CuA dams (N=10), and 1.81±0.07 in pups of CuD dams (N=18). CCO activity was lower (P<0.05, Tukey's test) in pups of CuDdams cross fostered to CuA dams compared to pups of CuA dams or pups of CuA dams cross fostered to CuD dams, but higher (P<0.05) compared to pups of CuD dams. Differences in heart Cu concentrations corresponded to the differences in CCO activity. These findings indicate that Cu intake during pregnancy has a greater influence than postnatal Cu intake on cardiac CCO in the first generation. [ABSTRACT FROM AUTHOR]