The effects of retinoblastoma (Rb) deletion on intestinal lipid absorption

Abstract

BackgroundThe Retinoblastoma protein (Rb) may play a role in modulating the absorption of lipids within the small bowel. Rb null mice are characterized by an increased intestinal surface area compared to wild‐type (WT) mice. This study investigates the effects of Rb deficiency on lipid absorptive capacity with normal and high fat diets.MethodsRb null and WT mice were maintained on normal and high fat diets for short and long–term periods. Mice where weighted weekly. Fat absorption and fecal fat were determined using an extraction protocol. Lean mass and body fat were determined via nuclear magnetic resonanceResultsNo differences in weight were found between Rb null and WT mice. The Rb null mice on normal chow had higher fecal fat compared to WT; however no significant difference in fat absorption was seen between the groups. Similar results were observed after the same mice were placed on a short‐term high fat diet. An extended high fat diet showed Rb null mice maintained a higher fecal fat while fat absorption increased in WT mice. No significant differences in body fat or lean mass were found between Rb null and WT mice on a prolonged high fat diet.ConclusionRegardless of the type of diet given, Rb null mice absorb lipids at a lower capacity compared to WT mice. Enhanced bowel surface area seems to serves no advantage in regards to lipid absorption.Research supported by NIH grant DK 59288‐06A2