Butyrylcholinesterase activity in plasma of rats and rabbits fed high-fat diets

1. 1. Comparative studies with rats and rabbits were carried out to address the question as to whether the amount of dietary fat affects butyrylcholinesterase (EC 3.1.1.8.) activity in plasma. 2. 2. Plasma butyrylcholinesterase activities were about 5-fold higher in rabbits than rats. 3. 3. Ad libitum feeding of diets enriched with corn oil caused increased body weights in rabbits but not in rats. 4. 4. Plasma butyrylcholinesterase activities of rats were increased with increasing intakes of corn oil. In rabbits, such an effect could not be demonstrated conclusively. 5. 5. Evidence is presented that in rats the substitution of dietary corn oil for isocaloric amounts of either carbohydrates or protein produces similar increases in plasma butyrylcholinesterase activity. 6. 6. This suggests that among macronutrients the amount of fat primarily determines butyrylcholinesterase activity in the plasma of rats.