Benzo(a)pyrene (B(a)P) metabolism and in vitro formation of B(a)P-DNA adducts by hepatic microsomes from rats fed diets containing corn and menhaden oils
Dietary unsaturated fat is required for maximum induction of hepatic mixed function oxidases responsible for activating carcinogens which may bind covalently to DNA. The aim of this study was to assess the influence of dietary fat type on in vitro B(a)P metabolism and B(a)P-DNA adduct formation. Male rats were starved 2 days and refed diet devoid of fat, or containing 20% corn oil (CO) or 20% menhaden oil (MO) for 4 days. Both dietary fats increased Vmax for B(a)P hydroxylation without affecting Km. Phenobarbital (PB) administration increased Vmax in all animals but Km was increased only in rats fed the fat diets. PB resulted in decreased B(a)P metabolism when conducted at 15 =M only in rats fed the two fat diets even in the presence of increased cytochrome P-450 (P-450). This effect was due to a decrease in B(a)P metabolism at low substrate concentrations in PB treated fat-fed animals. Binding of B(a)P to calf-thymus DNA was increased in animals fed both fats which was enhanced further by PB only in rats fed the CO and MO diets. When the data are calculated as B(a)P metabolized per unit of P-450, PB seems to induce a P-450 in fat-fed animals having lower affinity and capacity for B(a)P metabolism and activation.
- Research Organization:
- Univ. of Georgia, Athens
- OSTI ID:
- 5321503
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BENZOPYRENE
DNA ADDUCTS
METABOLISM
AFFINITY
CALVES
DIET
DNA
FATS
IN VITRO
LIVER
MICROSOMES
PHENOBARBITAL
RATS
THYMUS
ADDUCTS
ANESTHETICS
ANIMALS
ANTICONVULSANTS
AROMATICS
AZINES
BARBITURATES
BODY
CATTLE
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CONDENSED AROMATICS
DIGESTIVE SYSTEM
DOMESTIC ANIMALS
DRUGS
GLANDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYPNOTICS AND SEDATIVES
LYMPHATIC SYSTEM
MAMMALS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANOIDS
ORGANS
PYRIMIDINES
RODENTS
RUMINANTS
VERTEBRATES
550500* - Metabolism