Coassimilation of dietary fat and benzo(a)pyrene in the small intestine: an absorption model using the killifish
Benzo(a)pyrene (BP) was dissolved in dietary fat and fed in a single dose to killifish (Fundulus heteroclitus). Fluorescence microscopic examinations of small intestinal content and frozen sections of whole small intestine revealed that during fat digestion BP was codispersed in liquid crystalline product phases produced during lipolysis and then coabsorbed with dietary lipid followed by its reappearance in intracellular fat droplets. During the time that the absorbed fat remained in the enterocytes, BP fluorescence was initially concentrated in the intracellular fat droplets and then spread throughout the cytosol of the enterocytes. Tissue analyses showed that BP was rapidly metabolized in the intestine and transported to the gallbladder. These studies show that separation of a dissolved hydrophobic carcinogen from dietary fat occurs primarily after the fat has been digested, dispersed, absorbed, and reassembled in the enterocyte. The inability of the enterocyte to discriminate between dietary fat and dissolved carcinogenic compounds may be a partial explanation of the observed link between high fat diets and the incidence of some cancers. In vertebrates, the intestine and not the liver, appears to be the major site of metabolism of dietary polycyclic aromatic hydrocarbons (PAHs).
- Research Organization:
- Univ. of Georgia, Athens
- OSTI ID:
- 5175839
- Journal Information:
- J. Lipid Res.; (United States), Vol. 4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BENZOPYRENE
INTESTINAL ABSORPTION
METABOLISM
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MODELS
DIET
FISHES
FLUORESCENCE
LIPIDS
SMALL INTESTINE
ABSORPTION
ANIMALS
AQUATIC ORGANISMS
AROMATICS
BODY
CONDENSED AROMATICS
DIGESTIVE SYSTEM
GASTROINTESTINAL TRACT
HYDROCARBONS
INTESTINES
KINETICS
LUMINESCENCE
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
UPTAKE
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
550500 - Metabolism