Expression of P-glycoprotein in the chicken.
The multidrug resistance gene product, P-glycoprotein, may act as a defense mechanism against natural and man-made environmental toxins. Like mammals, chickens show high levels of P-glycoprotein expression in the liver, small intestine, and kidney. Expression of P-glycoprotein rapidly increased with age in the liver and kidney reaching a plateau by 2 and 4 days of age, respectively; however, expression of P-glycoprotein in the duodenum did not significantly change with age. Addition of dietary antibiotics (monensin, bacitracin), as models for dietary toxins, altered P-glycoprotein expression. Monensin increased P-glycoprotein expression in the liver and duodenum. Bacitracin reduced P-glycoprotein expression by 45% in the liver, but did not alter expression in the duodenum. Intraperitoneal injection of E. coli lipopolysaccharide, a model for acute inflammation, rapidly increased expression of Pgp protein in the liver ( approximately 2-fold). Expression then declines to pre-induction levels by 24 h. Similar responses were observed in the spleen and kidney but not the duodenum. These results confirm the presence of an avian P-glycoprotein homologue and suggest that dietary constituents regulate the expression of P-glycoprotein. Changes in P-glycoprotein expression may represent an important physiological response to foods containing toxins and an important component of the acute phase immune response.
Barnes
D M
DM
Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA. barnes@calshp.cals.wisc.edu
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000375:Aging / Q000378:metabolism; D000822:Animal Husbandry; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology; D001414:Bacitracin / Q000008:administration & dosage / Q000494:pharmacology; D002645:Chickens / Q000235:genetics / Q000378:metabolism*; D004032:Diet; D004926:Escherichia coli; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D014018:Tissue Distribution
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000900:Anti-Bacterial Agents; D008070:Lipopolysaccharides; D001414:Bacitracin