Copper status and ascorbic acid concentrations in rats

Abstract

Copper is a trace element essential for several biological systems. Important cuproenzymes, peptidylglycine α-amidating monooxygenase (PAM) and dopamine-β—monooxygenase (DBM), also require ascorbic acid (AA) as a cosubstrate for normal activity. To extend previous studies in mice, AA was determined in organs from thirty-day-old copper-adequate (+Cu) and copper-deficient (-Cu) male and female rats. Copper deficiency was initiated during the last two weeks of gestation and verified by the severe reduction in liver and brain copper concentrations, 85 and 75% respectively. Rat tissue AA concentrations were determined by HPLC with electrochemical detection. Brain, liver, and kidney were not influenced by diet while spleens from -Cu rats contained 20% less AA than controls. In a second study, male weanling rats were fed a -Cu diet for 5.5 weeks and compared to +Cu controls. Sixty-day-old male rats, +Cu and -Cu, had comparable AA levels but differing Cu status. Changes in PAM and DBM activity in -Cu rats are not likely to be influenced by changes in AA. Brain cortex and cerebellum AA levels were determined between birth and 6-weeks of age in control rats. A marked rise in cerebellar AA was noted during lactation which fell upon weaning.