Fat-based (Intralipid 20%) versus carbohydrate-based total parenteral nutrition: effects on hepatic structure and function in rats.

The role of fat-based total parenteral nutrition (TPN) in preventing or ameliorating hepatic dysfunction during TPN was investigated. Adult ACI-N rats were given fat-free carbohydrate-based TPN or isocaloric, isonitrogenous fat-based TPN (50% cal from 20% Intralipid, 50% cal from carbohydrate) for 7 days with Purina Chow-fed and fasting rats as controls. After fat-based TPN as compared with Chow or carbohydrate-based TPN, serum alkaline phosphatase activity and cholesterol levels doubled. Fatty infiltration and periportal inflammation in the liver were more marked. Both the TPN regimens were equally effective in maintaining body weight, positive nitrogen balance, muscle and hepatic protein content. Hepatic dysfunction in rats during TPN was not prevented by using a fat emulsion to provide 50% of the caloric requirement; the optimal proportion of fat as energy substrate in this system is less than 50%.