Studies on the Relationships between Nutrients and Metabolism of Body Fat

Part 1 Effects of the Dietary Fat and Protein on the Activities of Liver Choline Oxidase and Lipase

Abstract

Aalmost all of the studies on the dietary reqirements of nutrients have been proceeded by external investigations such as the measuring of the body weight, the lactation and the reproduction. We have attempted to research these dietary reqirements from the stand point of metabolism:
At the beginning, we studied the relationships between nutrients and the activities of enzymes in body.
In this paper the effects of the amounts of fat or protein given to rats on the activities of the several enzymes which metabolize lipid, i.e. liver choline oxidase and liver lipase are described.
Findings indicate that there seems to be little interrelationships between the levels of. fat in the diet and activities of choline oxidase or lipase on both ad libitum feeding and paired feeding experiments. When the protein levels were changed, the activity of choline oxidase increased in proportion to the increase of protein levels from 0 to 30% and kept the plateau thereafter, but the, lipase activity dropped only at the 0% level of protein.
Based upon the growth data, if the protein, vitamins, salts and Cal. intake were equal, the rate of gain in body was higher when the diet containning fat was fed.
These differences could not be seen when the large amount of thiamine and riboflavin are added. Contrasting to the protein, we might be able to suppose that the effects of fat on the metabolic turnover would be little. It must be, however, clarified by additional experiments, of course. We are continuing further studies on-this subject now.