Metabolic interaction among fat and glucose during total parenteral nutrition

To investigate the efficacy of intravenous fat emulsion for total parenteral nutrition (TPN), oxidation of fat was evaluated using (14)C labeled nutrients in rats. Animals were divided into five group depending the content of fat emulsion of TPN e. i. 0%, 20%, 40%, 60%, and 80%, respectively. Oxidation rate of intravenous glucose was unaffected by content of fat emulsion. Cumulative (14)CO(2) production for 7 hours was about 62% in all groups. On the other hand, the oxidation rate of intravenous fat emulsion was suppressed by increased glucose content. There was a negative linear relationship between oxidation rate of intravenous fat and glucose intake (r=-0.92, p<0.01). The oxidation rate of intravenous fat was increased proportionaly to fat intake and not completely suppressed when fat-free TPN was provided. Percentage of energy to be infused as fat should be about 20%.