Differential induction of (/sup 14/C)benzo(a)pyrene metabolism in tissues of the rat placenta

Conference · Sat Mar 01 00:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5447072

Salhab, A; James, M O; Wang, S L; Shiverick, K T

The authors have previously reported the differential induction by ..beta..-naphthaflavone (..beta.. NF) of ethoxyresorufin-O-deethylase activity in the labyrinth (LA) tissue of the rat placenta. This study characterized the metabolism of (/sup 14/C)benzo(a)pyrene (BP) in microsomes prepared from the respective LA and basal zone (BZ) portions of the placenta. Pregnant rats (day 14 gestation) received ..beta.. NF (15 mg/kg, i.p.) or 3-methylcholanthrene (3 MC; 30 mg/kg, i.p.). On day 15 placental were dissected and microsomes were incubated with 16 ..mu.. M (/sup 14/C)BP and 10 mM NADPH. BP metabolites were separated by HPLC on a reverse phase column. Only trace BP metabolism occurred in BZ microsomes from control (C), ..beta.. NF- or 3MC- animals, or in LA microsomes from C animals. In contrast, LA microsomes from ..beta.. NF and 3MC rats actively converted BP to quinone (Q), phenolic (OH) and diol (D) products. Product formation in LA microsomes from 5 ..beta.. NF-animals was as follows: 1,6-Q, 0.86 +/- 0.18 pmoles/mg protein/min (X +/- SE); 3,6-Q, 0.80 +/- 0.21; 6,12-Q, 0.56 +/- 0.16; 9-OH, 0.44 +/- 0.13; 3-OH and 7-OH, 0.32 +/- 0.11; 4,5-D, 0.15 +/- 0.05; 7,8-D, 0.15 +/- 0.05; and 9,10-D, 0.04 +/- 0.01. The same pattern of BP metabolism was observed in LA microsomes from 3MC-animals, with quinones being the predominant product. Thus, data confirm that the labyrinth tissue is the major site of xenobiotic induction and metabolism in the rat placenta.

• Research Organization: Univ. of Florida, Gainesville
• OSTI ID: 5447072
• 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

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
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BENZOPYRENE
METABOLISM
ANIMAL TISSUES
CARBON 14 COMPOUNDS
CHOLANTHRENE
LIQUID COLUMN CHROMATOGRAPHY
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PREGNANCY
QUINONES
RATS
TRACER TECHNIQUES
ANIMALS
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COENZYMES
CONDENSED AROMATICS
FETAL MEMBRANES
HYDROCARBONS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANOIDS
RODENTS
SEPARATION PROCESSES
TISSUES
VERTEBRATES
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