Independent effects of diet and nutritional status on apoprotein B gene expression in rabbit.

The separate effects of dietary composition and time of nutrient intake on apoprotein B (apo B) gene expression in rabbit intestine and liver were determined. After an overnight fast, there were insignificant effects of the long-term consumption of a diet containing saturated fat on the tissue levels of apo B mRNA, although plasma cholesterol levels were elevated as compared to those of animals consuming a diet containing unsaturated fat. However, when the animals were studied 2 hours after receiving a gastric tube feeding of a portion of their test diets after an overnight fast, there was a twofold increase in the intestinal apo B mRNA level and a similar increase in the transcriptional activity of the apo B gene independent of dietary composition. We conclude that, with the diets we used, nutrient intake alone has, in rabbits, a major effect on apo B gene expression at the level of transcription. This factor should be taken into account when designing studies of intestinal gene expression.