The Control of Lipogenesis by Dietary Linoleic Acid and Its Influence on the Deposition of Fat

Abstract

The replacement of dietary starch by sucrose results in an increase in hepatic lipogenesis in the rat. When corn oil (4% by wt or 9% of the energy content of the diet) was included with the sucrose (20% by wt, 20% of the energy content) the lipogenic effect of the sucrose was completely suppressed. When beef tallow replaced the corn oil the induced activity caused by the sucrose was reduced by only .apprxeq. 20%. No significant differences were observed between males and females. These diets containing sucrose supplemented with 4% (wt/wt) corn oil or 4% (wt/wt) beef tallow were used to ascertain whether the effects on hepatic lipogenesis were reflected in changes in the amount of fat deposited during growth from 4-24 wk of age. The percentage body fat was statistically different (P < 0.05) when animals fed sucrose-supplemented diets were compared to animals fed diets supplemented with sucrose and beef tallow. There were no significant differences in total carcass weight of the rats. The results are discussed in terms of the relative contribution of liver and adipose tissue to total lipogenesis and the factors which control the lipogenic activity in the 2 tissues.