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- Author or Editor: Dorothy E. Farrell x
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Abstract
Objective—To determine whether there is a relationship between species-specific mitochondrial DNA (mtDNA), especially canine and feline mtDNA, and detectable amounts of pentobarbital in previously analyzed dog food samples.
Sample Population—31 dog food samples previously analyzed for pentobarbital (limit of detection, 1 µg/kg).
Procedure—Polymerase chain reaction (PCR) analysis was performed on dog food samples by use of PCR primers specific for either canine, feline, equine, bovine, porcine, ovine, or poultry mtDNA.
Results—PCR amplicons specific for feline or canine mtDNA at a 0.007% (70 µg/g [wt/wt basis]) or 0.0007% (7 µg/g) level, respectively, were not found in the 31 dog food samples. Most of the 31 dog food samples had a PCR amplicon on PCR analysis when a PCR primer set capable of simultaneously detecting mtDNA of cows, pigs, sheep, goats, deer, elk, and horses was used. Results of PCR analysis by use of primers specific for bovine, swine, sheep and goat, or horse mtDNA revealed amplicons specific for bovine or swine mtDNA only in 27 of the 31 samples. Analysis of the remaining 4 samples failed to yield amplicons for any mammalian mtDNA. Pentobarbital was detected in 2 of these 4 samples. Results of PCR analysis correlated with the stated ingredient list for most, but not all samples.
Conclusions and Clinical Relevance—Because canine and feline mtDNA were not found in a set of retail dog food samples, these results indicate that the source of pentobarbital in dog food is something other than proteins from rendered pet remains. ( Am J Vet Res 2004;65:99–103)
Abstract
Objective—To investigate effects of bacteria-mediated inflammation on hepatic drug metabolizing enzymes (DMEs) in swine via a lipopolysaccharide (LPS) challenge technique.
Animals—22 Poland China–Landrace crossbred barrows.
Procedures—In experiment 1, 10 market-weight swine were treated with LPS (20 μg/kg, IV [n = 5 swine]) or sham-injected (5) 24 hours before slaughter. In experiment 2, 12 growing and finishing swine were treated with LPS at 2 or 20 μg/kg, IV (n = 3 swine/age group/treatment) 24 hours before slaughter. Hepatic DMEs, cytochrome P450 (CYP) isoforms, and CYP-mediated reactions were measured.
Results—In experiment 1, LPS administered at 20 μg/kg decreased most hepatic DME components and inhibited enzymatic activities. In experiment 2, both doses reduced protein content in subcellular fractions and inhibited some DME- and CYP-mediated activities. In growing and finishing swine, CYP2A and CYP2B isoforms were not detected after treatment with LPS; the CYP1A2 isoform was eliminated in growing but not in finishing swine. Lipopolysaccharide also reduced CYP2D6 content in growing and finishing swine but increased CYP2E content. Lipopolysaccharide had no effect on swine CYP2C11, CYP2C13, or CYP3A content. The CYP2B-mediated 7-pentoxyresorufin O-dealkylase activity in growing and finishing swine was totally eliminated, and 7-ethoxyresorufin (indicating CYP1A activity) and aniline (mediated by CYP2E) metabolism was decreased.
Conclusions and Clinical Relevance—Effect of LPS treatment on swine CYPs appeared to be isoform specific; age-related metabolic status of the swine and the LPS dose modified this effect. Lipopolysaccharide-induced inflammation may affect metabolism of drugs and xenobiotics in swine.
Abstract
Objective—To determine the effect of oral administration of low doses of pentobarbital on cytochrome P450 (CYP) isoforms and CYP-mediated reactions in immature Beagles.
Animals—42 immature (12-week-old) Beagles.
Procedure—Dogs were grouped and treated orally as follows for 8 weeks: low-dose pentobarbital (50 µg/d; 4 males, 4 females), mid-dose pentobarbital (150 µg/d; 4 males, 4 females), high-dose pentobarbital (500 µg/d; 4 males, 4 females), positive-pentobarbital control (10 mg/kg/d; 2 males, 2 females), positivephenobarbital control (10 mg/kg/d; 2 males, 2 females), and negative control (saline [0.9% NaCl] solution; 5 males, 5 females). Serum biochemical and hematologic values were monitored. On necropsy examination, organ weights were determined, and histologic evaluation of tissue sections of liver, kidney, small intestine, testes, epididymis, and ovaries was performed. Hepatic and intestinal drug-metabolizing enzyme activities were measured, and relative amounts of CYP isoforms were determined by western blot analysis.
Results—The amount of a hepatic CYP2A-related isoform in dogs from the high-dose pentobarbital treatment group was twice that of dogs from the negative control group. CYP2C was not detectable in small intestinal mucosa of dogs from the negative control group; measurable amounts of CYP2C were found in dogs from the various (low-, mid-, and high-dose) pentobarbital treatment groups and from positive-pentobarbital and positive phenobarbital control groups. Several CYP-mediated reactions increased in a dosedependent manner. The lowest calculated effective dose of pentobarbital ranged from 200 to 450 µg/d.
Conclusions and Clinical Relevance—Several CYP isoforms and their associated reactions were induced in dogs by oral administration of low amounts of pentobarbital. (Am J Vet Res 2003;64:1167–1175)
