Isolation and characterization of rat intestinal polyribosomes and RNA during absorption of fat. Increased translation in vitro of apo-AIV.

Polyribosomes were isolated from the intestinal mucosa of fasted and fat-fed rats in the presence of ribonuclease inhibitors. Polyribosomes from fat-fed rats were larger and more efficient in incorporating radioactive aminoacids into proteins than those from fasted rats. Total RNA prepared by guanidine-HCl extraction, from the intestine of fasting and fat-fed rats were translated in vitro in a mRNA-dependent rabbit reticulocyte lysate system in the presence of 35S-methionine. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography of the synthesized peptides showed a relative increase in the radioactivity of some peptides of RNA from fat-fed animals and particularly a two fold increase in preapo-AIV indicating that the intestinal apo-AIV synthesis is under transcriptional regulation by the metabolic processes involved in fat transport, that is, triglyceride-rich lipoprotein production.