Ah receptor involvement in mediation of pyruvate carboxylase levels and activity in mice given 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin
作者:
Byung‐Woo Ryu,
Shukla Roy,
Barney R. Sparrow,
Daniel P. Selivonchick,
Henry W. Schaup,
期刊:
Journal of Biochemical Toxicology
(WILEY Available online 1995)
卷期:
Volume 10,
issue 2
页码: 103-109
ISSN:0887-2082
年代: 1995
DOI:10.1002/jbt.2570100207
出版商: Wiley Subscription Services, Inc., A Wiley Company
关键词: Pyruvate Carboxylase;Ah Receptor;TCDD;2,3,7,8‐tetrachlorodibenzo‐p‐dioxin;Corn Oil;Congenic Mouse
数据来源: WILEY
摘要:
AbstractThe arylhydrocarbon receptor (AhR) plays a central role in mediating 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) toxicity in animals. The investigations described here provide evidence that support a role for the AhR in TCDD‐mediated pyruvate carboxylase (PC) level/activity reductions in mice. Pyruvate carboxylase plays a pivotal role in gluconeogenesis and in supplying carbon units for the citric acid cycle. Delivered ip in a corn oil carrier, TCDD suppresses PC activity/amount at doses as low as 1 μg/kg in responsive C57BL/6J(Ahb/b) mice. Corn oil alone injected ip into mice at 4 mL/kg appears to be an inducer that increases the amount and activity of PC. However, TCDD suppresses this induction. In the Ahb/bmouse, PC levels and activity are reduced to 10% of control values at a dose of 75 μg/kg. A time‐course experiment shows that the PC reductions are apparent within 16 hours post‐TCDD exposure. Here we report investigations on the PC/TCDD response using a congenic C57BL/6J(Ahd/d) mouse strain having an AhR with a low affinity for TCDD. If the PC/TCDD response is AhR mediated, the congenic mouse strain (Ahd/d) would require much higher doses of TCDD to suppress PC. In the Ahd/dmice, we observe that an approximately 60‐fold increase in TCDD dose is necessary to produce a PC/TCDD effect. We also find that in Ahd/dmice, corn oil does not induce an increase in PC activity/amounts, as reporte
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