Effect of Age and Sex on Triglyceride Metabolism in the Rat

The effect of age and sex on triglyceride metabolism were investigated in 3-mo- and 1-year-old rats. Although 3-mo-old female rats produce as much triglyceride as comparably aged male rats, their plasma triglyceride levels are lower. This suggests that 3-mo-old female rats remove triglycerides from plasma more efficiently than do similar aged male rats, and this is supported by the observation that the t1/2 of very low density lipoprotein triglyceride removal is somewhat faster in female rats of this age (p less than 0.1 greater than 0.5). As rats grow to 1 year of age, the ability of both sexes to remove triglycerides from plasma deteriorates, resulting in a rise in plasma triglyceride levels. The decrease in efficiency of triglyceride removal from plasma in female rats is coupled with an increase in triglyceride production rate, leading to an even greater increase in triglyceride levels. These results indicate that both age and sex modify triglyceride metabolism in the rat.