Toxicological sciences : an official journal of the Society of Toxicology
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This study was conducted to assess spinal safety of the cyclo-oxygenase inhibitor ketorolac in dogs and rats. Beagle dogs were prepared with lumbar intrathecal catheters and received continuous spinal infusions of 5 mg/ml ketorolac (N = 6), 0.5 mg/ml ketorolac (N = 8), or saline vehicle (N = 6) at 50 microl/h (1.2 ml/day) for 28 days. No systematic drug or dose-related changes were observed in motor function, heart rate, or blood pressure. ⋯ Bolus and continuous infusion of intrathecal ketorolac resulted in significant reduction of lumbar CSF PGE2 concentrations. In rats, with intrathecal catheters, four daily bolus deliveries of saline or ketorolac (5 mg/ml/10 microl) had no effect upon spinal histology or upon spinal cord blood flow. These data indicate that intrathecal ketorolac in two species at the dose/concentrations employed does not induce evident spinal pathology but diminishes spinal prostaglandin release.
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CYP2E1 and CYP4A11 are cytochrome P450 enzymes that are regulated by physiological conditions including diabetes and fasting. In addition, the xenochemical clofibrate has been reported to induce both rodent CYP2E1 and CYP4A. These findings suggest similar modes of regulation. ⋯ Palmitic acid significantly (p < 0.05) increased CYP2E1 mRNA to 326 +/- 57% of control. Collectively, results presented here identify agents that enhance CYP2E1 and CYP4A11 at the transcription level and suggest that fatty acids may represent a similar mode of regulation for these P450 enzymes. The lack of induction of CYP2E1 protein by ethanol in human hepatocytes indicates that for certain P450 enzymes, isolated hepatocytes may not be an adequate tool for predicting in vivo responses.
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The effects of a chronic aluminum (Al) exposure on biliary secretory function, with special emphasis on hepatic handling of non-bile salt organic anions, was investigated. Male Wistar rats received, intraperitoneally, either 27 mg/kg body weight of Al, as Al hydroxide [Al (+) rats], or the vehicle saline [Al (-) rats] three times a week for 3 months. Serum and hepatic Al levels were increased by the treatment (approximately 9- and 4-fold, respectively). ⋯ These results show that chronic Al exposure leads to oxidative stress, cholestasis, and impairment of the hepatic handling of organic anions by decreasing both sinusoidal uptake and canalicular excretion. The alteration of the latter process seems to be causally related to impairment of Mrp2 expression. We have addressed some possible mechanisms involved in these deleterious effects.
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Comparative Study
In utero and lactation exposure of rats to 1R4F reference cigarette mainstream smoke: effect on prenatal and postnatal development.
Childhood cognitive and behavioral deficits have been reported in children born to mothers who smoked during pregnancy (Institute of Medicine, 2001). To investigate these potential responses in an animal model, reproductive and neurotoxicity evaluations based on the U. S. ⋯ Maternal toxicity occurred at concentrations of 300 and 600 mg TPM/m(3), where total body weight gain during gestation was significantly (p < or = 0.05) decreased compared to sham controls. While smoke concentration-related decreases in F(1) birth weight and growth were evident (600 mg TPM/m(3), significantly different from sham at all time points), no adverse effects on developmental landmarks, including age at vaginal patency or preputial separation, motor activity, acoustic startle response or learning, and memory, were observed in the F(1) generation. This study confirmed that maternal exposure to high levels of mainstream cigarette smoke during gestation and lactation reduces birth weight and retards growth in the rat neonate; however, the developmental and neurobehavioral testing methodologies employed did not appear to be sensitive for an evaluation of neonatal behavioral effects following parental smoke exposure.
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Comparative Study
In utero exposure to 1R4F reference cigarette smoke: evaluation of developmental toxicity.
The potential developmental effects of 1R4F reference cigarette smoke were examined using Sprague-Dawley rats exposed for 2 h/day, 7 days/week, by nose-only inhalation at target mainstream smoke concentrations of 150, 300, and 600 mg/m3 total particulate matter (TPM). Males were exposed 4 weeks prior to and during mating, with females exposed 2 weeks prior to mating and during mating, and through gestation day (GD) 20. Sham controls received filtered air to simulate nose-only exposure, while cage controls were maintained untreated. ⋯ Skeletal examinations revealed delayed ossification (supra occipital and sternebrae) in fetuses from dams exposed to 300 or 600 mg TPM/m3 smoke. High concentrations of 1R4F cigarette smoke were not teratogenic. The methodology used for this study was able to detect a decrease in fetal birthweight and this approach may be a useful tool for cigarette evaluation.