Effect of ethionine on carbohydrate and lipid metabolism

In ethionine-treated rats, the ATP content of adipose tissue was not decreased whereas in liver it was drastically reduced to about one-fifth of the control level. Shortly after the injection of ethionine, hepatic glycogen was depleted and the blood glucose concentration fell from 120 to 80 mg/100 ml. This was followed by a two- to threefold elevation of the plasma fatty acid level. Hepatic glucose-6-phosphate was decreased and was not elevated by administration of 2 mmoles of glucose unless ATP was partially restored to normal levels. When hepatic ATP was decreased, the disappearance of [(14)C]glucose from the blood and its incorporation into glycogen and glyceride-glycerol and the incorporation of [3-(14)C]pyruvate into glyceride-glycerol were reduced. 6 hr after ethionine injection the plasma triglyceride level fell but there was no significant change in the liver triglyceride concentration, but by 24 hr it had increased markedly. Lipogenesis in adipose tissue was depressed in vivo, possibly due to decreased glycerol-3-phosphate concentrations. A marked decrease of glycerol-3-phosphate in both liver and adipose tissue was noted. Administration of glucose effectively depressed plasma free fatty acid concentration and elevated the glycerol-3-phosphate levels. Ethionine injection to fasted animals further depressed the blood glucose and elevated the plasma free fatty acid level.