Correlation between intravenously supplied energy level and zinc metabolism in laparotomized rats

We investigated the relationship between intravenous energy loading and zinc status in laparotomized rats. One of three test solutions consisting of 3% amino acid, the same amount of electrolytes (excluding zinc) and different concentrations of glucose were infused through the jugular vein for 5 d. The total energy was 109, 191 and 273 kcal/kg/d, respectively. Significantly positive correlations were observed between infusion energy and rat body weight changes (% of initial value) and between infusion energy and cumulative nitrogen balance. Regarding the zinc status, a negative correlation was found between infusion energy and plasma zinc concentration, and a positive correlation was observed between infusion energy and urinary zinc excretion. There was no significant relationship between infusion energy and hepatic zinc content. These results indicate that the zinc requirement might be increased when infusion energy is elevated and the nutritional status is improved. Zinc supplementation in the post-operative period should be considered in light of not only catabolism but also anabolism. Anabolism may be more important than catabolism in regard to zinc metabolism under relatively mild stress.