The effect of chlorpyrifos and chlorpyrifos-oxon on brain cholinesterase, muscarinic receptor binding, and neurotrophin levels in rats following early postnatal exposure.

Chlorpyrifos (CPS) is a widely used diethyl organophosphorus insecticide in agricultural settings. Household and urinary residue analysis has suggested that children in agricultural communities are at risk of exposure to diethyl organophosphorus insecticides. The effects of repeated postnatal exposure to CPS and its metabolite chlorpyrifos-oxon (CPO) on total muscarinic acetylcholine receptor (mAChR) binding, nerve growth factor (NGF) levels, and brain derived neurotrophic factor (BDNF) levels in the forebrain of neonatal rats were investigated. Peak inhibition of brain cholinesterase (ChE) for CPS and CPO was determined after acute exposure to dosages of each compound (a low and a high for each), which produced similar degrees of initial ChE inhibition. Pups were administered CPS (1.5 or 3.0 mg/kg), CPO (0.25 or 0.35 mg/kg), or the corn oil vehicle by daily gavage from postnatal day 1 (PND 1) through PND 6. This exposure paradigm resulted in persistent ChE inhibition by CPS but only transient inhibition by CPO, suggesting that, even though the initial ChE inhibition is similar between compounds, the effects of repeated exposure differ significantly. Forebrain mAChR density, as measured by the binding of 3H-QNB, and NGF levels were significantly reduced on PND 4 and 7 after CPS but not on PND 12. No effects on mAChR density or NGF levels were observed with CPO. No effects on BDNF levels were observed with either compound. The data suggest that the persistent ChE inhibition and decreased mAChR binding may play a role in the decreased NGF levels following CPS exposure.     

Developmental toxicity studies in rats and rabbits with 3,5,6-trichloro-2-pyridinol, the major metabolite of chlorpyrifos.

3,5,6-Trichloro-2-pyridinol (TCP), the primary metabolite of chlorpyrifos and chlorpyrifos-methyl, was evaluated for potential developmental toxicity. Groups of 32-34 bred female Fischer 344 rats were given 0, 50, 100, or 150 mg TCP/kg/day by gavage on gestation days 6-15; the fetuses were evaluated on gestation day 21. Similarly, groups of 16 inseminated female New Zealand White rabbits were given 0, 25, 100, or 250 mg TCP/kg/day by gavage on gestation days 7-19, and fetuses were evaluated on gestation day 28. No clinical signs of toxicity attributed to TCP were noted in either species. In rats, at 150 mg/kg/day, maternal effects included slight decreases in feed consumption, significantly depressed body weight gain (25% relative to controls) resulting in significantly lower maternal terminal body weights, and increased relative liver weight. At 100 mg/kg/day, maternal body weight gain in rats was depressed approximately 22%. Among rabbits, maternal effects were limited to the group given 250 mg/kg/day, which lost an average of approximately 70 g during the treatment period (vs. 140 g in the controls). There were no effects on fetal weight or viability, nor were there significant increases in any fetal alteration in either species. A slightly higher (not statistically significant) than usual incidence of central nervous system anomalies occurred in rabbits, but these anomalies were found in both treated and control groups in this study as well as contemporaneous studies of unrelated compounds. This, and the fact that these anomalies were not seen with the parent compound, chlorpyrifos, suggest that their origin was spontaneous. Thus, TCP was not considered fetotoxic or teratogenic in either rats or rabbits, even at dose levels that produced maternal toxicity.     

Neurochemical effects of chronic dietary and repeated high-level acute exposure to chlorpyrifos in rats.

Very little is known about the effects of chronic exposure to relatively low levels of anticholinesterase insecticides or how the effects of chronic exposure compare to those of higher, intermittent exposure. To that end, adult male rats were fed an anticholinesterase insecticide, chlorpyrifos (CPF), for 1 year at three levels of dietary exposure: 0, 1, or 5 mg/kg/day (0+oil, 1+oil, and 5+oil). In addition, half of each of these groups also received a bolus dosage of CPF in corn oil ("spiked" animals; 60 mg/kg initially and 45 mg/kg thereafter) every 2 months (0+CPF, 1+CPF, 5+CPF). Animals were analyzed after 6 or 12 months of dosing, and again 3 months after cessation of dosing (i.e., "recovery" animals-six experimental groups with n = 4-6/group/time point). Cholinesterase (ChE) activity was measured in retina, whole blood, plasma, red blood cells, diaphragm, and brain [pons, striatum, and the rest of the brain (referred to simply as "brain")]. Muscarinic receptor density was assessed in retina, pons, and brain, whereas dopamine transporter density and the levels of dopamine and its metabolites were assessed in striatum. Cholinesterase activity at 6 and 12 months was not different in any of the tissues, indicating that a steady state had been reached prior to 6 months. The 1+oil group animals showed ChE inhibition only in the blood, whereas the 5+oil group exhibited > or = 50% ChE inhibition in all tissues tested. One day after the bolus dose, all three groups (0+CPF, 1+CPF, 5+CPF) showed > or = 70% ChE inhibition in all tissues. Muscarinic receptor density decreased only in the brain of the 5+oil and 5+CPF groups, whereas dopamine transporter density increased only at 6 months in all three spiked groups. Striatal dopamine or dopamine metabolite levels did not change at any time. Three months after CPF dosing ended, all end points had returned to control levels. These data indicate that, although chronic feeding with or without intermittent spiked dosages with CPF produces substantial biochemical changes in a dose- and tissue-related manner, there are no persistent biochemical changes.     

大蒜素对新生乳鼠肠道细菌移位的影响

目的考察大蒜素对新生乳鼠肠道细菌移位的作用。方法乳鼠140只随机分为10组:0,1,7,14,28 d空白对照组和0,1,7,14,28 d大蒜素组,每组14只。空白对照组腹腔注射0.9%氯化钠注射液0.03 mL/g,1次/d;大蒜素组腹腔注射大蒜素注射液0.005 mg/g,1次/d。0 d组在出生后即处死,其余各组均在各时间点末次给药后20 min处死乳鼠并收集指标。结果与对照组比较,大蒜素连续28 d后,新生乳鼠体重显著增加(P<0.05),G+球菌和G-杆菌的浓度显著降低(P<0.05),乳酸杆菌的浓度无显著影响(P>0.05),肠系膜淋巴结、肝和脾的细菌浓度显著降低(P<0.05),细菌检出的阳性器官数也略低。结论大蒜素有助于建立新生乳鼠肠道细菌平衡。     

effect of atorvastatin on the pharmacokinetics of diltiazem and its main metabolite,desacetyldiltiazem, in rats

The purpose of this study was to investigate the effect of atorvastatin, HMG-CoA reductase inhibitor, on the pharmacokinetics of diltiazem and its active metabolite, desacetyldiltiazem, in rats. Pharmacokinetic parameters of diltiazem and desacetyldiltiazem were determined in rats after oral administration of diltiazem (15 mg x kg(-1)) to rats pretreated with atorvastatin (0.5 or 2.0 mg x kg(-1)). Compared with the control (given diltiazem alone), the pretreatment of atorvastatin significantly altered the pharmacokinetic parameters of diltiazem. The peak concentration (Cmax) and the areas under the plasma concentration-time curve (AUC) of diltiazem were significantly (p < 0.05, 0.5 mg x kg(-1); p < 0.01, 2.0 mg x kg(-1)) increased in the presence of atorvastatin. The AUC of diltiazem was increased by 1.40-fold in rats pretreated with 0.5 mg x kg(-1) atorvastatin, and 1.77-fold in rats pretreated with 2.0 mg x kg(-1) atorvastatin. Consequently, absolute bioavailability values of diltiazem pretreated with atorvastatin (8.4-10.6%)were significantly higher (p < 0.05) than that in the control group (6.6%). Although the pretreatment of atorvastatin significantly (p < 0.05) increased the AUC of desacetyldiltiazem, metabolite-parent AUC ratio (M.R.) in the presence of atorvastatin (0.5 or 2.0 mg x kg(-1)) was significantly decreased compared to the control group, implying that atorvastatin could be effective to inhibit the metabolism of diltiazem. In conclusion, the concomitant use of atorvastatin significantly enhanced the oral exposure of diltiazem in rats.     

肠道菌群对硫酸氢氯吡格雷及其活性代谢产物在大鼠体内药动学的影响

目的：探究肠道菌群变化对硫酸氢氯吡格雷及其活性代谢产物在大鼠体内药动学的影响。方法：24只健康大鼠随机分为益生菌组、抗生素组和对照组,每组8只,分别灌胃双歧杆菌乳杆菌三联活菌（0.8 g·kg^-1）、阿莫西林克拉维酸钾片（125 mg·kg^-1）和等体积的纯化水,连续7 d。第8天给予硫酸氢氯吡格雷片,并于给药前和给药后不同时间点取血于含有衍生试剂的抗凝管中,LC-MS/MS法测定血药浓度,绘制药时曲线,使用DAS 2.1.1拟合药动学参数,SPSS 21.0进行统计学比较。结果：益生菌组、抗生素组和对照组硫酸氢氯吡格雷和活性代谢产物衍生物（CAMD）的主要药动学参数AUC_0-t、AUC_0-∞、t_1/2、t_max、CL、V、C_max均没有统计学差异（P>0.05）。结论：肠道菌群变化对硫酸氢氯吡格雷及其活性代谢产物的药动学参数没有影响。     

Use of a pharmacokinetic model to assess chlorpyrifos exposure and dose in children, based on urinary biomarker measurements.

Chlorpyrifos is a common agricultural insecticide and has been used residentially in the United States until the year 2000 when this use was restricted by the U.S. Environmental Protection Agency (U.S. EPA). A chlorpyrifos metabolite, 3,5,6-trichloro-2-pyridinol (TCPy) has been found in urine samples collected during exposure field studies. In this work, we use urinary biomarker data and the inverse solution of a simple pharmacokinetic (PK) model for chlorpyrifos to estimate the magnitude and timing of doses. Three urine samples were collected on separate days from each of 15 children (ages 3-12) who were participants in the Minnesota Children's Pesticide Exposure Study (MNCPES). The total volume of urine was noted and samples analyzed for TCPY: The urinary data was used along with constraints imposed on dose timing, based on responses of the individuals to pesticide-use surveys. We predicted the time and magnitude of multiple "event" exposures characterized by short-term, relatively high doses superimposed over a continuous background exposure. The average dose of chlorpyrifos predicted by the model was 1.61 microg/kg per reported event. Average background dose rate for these children that reported exposure events was 0.0062 microg/kg/h, or 0.15 microg/kg/day. In addition to predicting the total dose of chlorpyrifos received by an individual from urinary biomarker measurements, the model can then be run in a forward manner once the exposure regime is determined. This will allow the prediction of the total amount of TCPy eliminated in the urine over any time period of interest.     

Alteration of neurotrophins in the hippocampus and cerebral cortex of young rats exposed to chlorpyrifos and methyl parathion.

Exposure to either chlorpyrifos (CPS) or methyl parathion (MPS) results in the inhibition of acetylcholinesterase and leads to altered neuronal activity which normally regulates critical genes such as the neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). The effects of postnatal exposure to CPS and MPS on the expression of messenger RNA (mRNA) and protein levels for NGF and BDNF were investigated in the frontal cerebral cortex (cortex) and hippocampus of rats. Oral administration of CPS (4.0 or 6.0 mg/kg), MPS (0.6 or 0.9 mg/kg), or the safflower oil vehicle was performed daily from postnatal day 10 (PND10) through PND20. Exposure induced significant effects on growth and cholinesterase activity. Increased NGF protein levels were observed in the hippocampus but not the cortex on PND20 with some reduction occurring on PND28 in both regions. These changes did not correlate with the changes in NGF mRNA. BDNF mRNA was increased in both regions on PND20 and PND28, whereas BDNF protein levels were increased on PND20. On PND12, c-fos mRNA, a marker of neuronal activation, was increased in both regions. Total BDNF protein was increased in the hippocampus but decreased in the cortex. No changes in NGF protein were observed. These results indicate that repeated developmental OP exposure during the postnatal period alters NGF and BDNF in the cortex and the hippocampus and the patterns of these alterations differ between regions.     

Neurobehavioral effects of chronic dietary and repeated high-level spike exposure to chlorpyrifos in rats.

This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos, and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult Long-Evans male rats were maintained at 350 g body weight by limited access to a chlorpyrifos-containing diet to produce an intake of 0, 1, or 5 mg/kg/day chlorpyrifos. During the year-long exposure, half of the rats in each dose group received bi-monthly challenges (spikes) of chlorpyrifos, and the other half received vehicle. Rats were periodically tested using a neurological battery of evaluations and motor activity to evaluate the magnitude of the acute response (spike days) as well as recovery and ongoing chronic effects (non-spike days). Effects of the spikes differed as a function of dietary level for several endpoints (e.g., tremor, lacrimation), and in general, the high-dose feed groups showed greater effects of the spike doses. Animals receiving the spikes also showed some neurobehavioral differences among treatment groups (e.g., hypothermia, sensory and neuromotor differences) in the intervening months. During the eleventh month, rats were tested in a Morris water maze. There were some cognitive deficits observed, demonstrated by slightly longer latency during spatial training, and decreased preference for the correct quadrant on probe trials. A consistent finding in the water maze was one of altered swim patterning, or search strategy. The high-dose feed groups showed more tendency to swim in the outer annulus or to swim very close to the walls of the tank (thigmotaxic behavior). Overall, dietary exposure to chlorpyrifos produced long-lasting neurobehavioral changes and also altered the response to acute challenges.     

The pharmacokinetics of aspirin in rats and the effect of buffer

Aspirin (acetylsalicyclic add) was administered to rats intravenously, orally, and intraintestinally at different doses or in different dosage forms. The distribution and elimination kinetics of aspirin in rats following intravenous administration were best described by a two-compartmental open system and were dose independent up to 15 mg/kg. The terminal elimination half-life following intravenous dosing (10 mg/kg) was 3.36±0.85min (n=15) with the clearance being 8.40±1.24 L/(kg.hr). Intravenous distribution and elimination kinetics of aspirin in rats were not influenced by an orally administered buffered solution with a buffer capacity of 0.933 mEq ANC (acid neutralizing capacity) per kg of body weight. However, this orally buffered solution did change the gastrointestinal absorption kinetics of aspirin in rats. The absolute bioavailable dose of aspirin was 56.6±10.4% (n=6)following its administration in an unbuffered solution while it was only 31.8±8.0% (n=6)following administration in the buffered solution. The corresponding values of the absolute bioavailable doses were 43.4±3.7% and 25.5±1.8% following intraintestinal administration. The lower systemic availability of aspirin in the presence of buffer is attributed to a greater fraction of the administered dose becoming available for absorption from the intestine where the extraction efficiency is higher than that in the stomach.     

Developmental neurotoxicity of organophosphorous pesticides: fetal and neonatal exposure to chlorpyrifos alters sex-specific behaviors at adulthood in mice.

Developmental exposure to the organophosphorous insecticide chlorpyrifos (CPF) induces long-term effects on brain and behavior in laboratory rodents. We evaluated in adult mice the behavioral effects of either fetal and/or neonatal CPF exposure at doses not inhibiting fetal and neonatal brain cholinesterase. CPF (3 or 6 mg/kg) was given by oral treatment to pregnant females on gestational days 15-18 and offspring were treated sc (1 or 3 mg/kg) on postnatal days (PNDs) 11-14. Serum and brain acetylcholinesterase (AChE) activity was evaluated at birth and 24 h from termination of postnatal treatments. On PND 70, male mice were assessed for spontaneous motor activity in an open-field test and in a socioagonistic encounter with an unfamiliar conspecific. Virgin females underwent a maternal induction test following presentation of foster pups. Both sexes were subjected to a plus-maze test to evaluate exploration and anxiety levels. Gestational and postnatal CPF exposure (higher doses) affected motor activity in the open field and enhanced synergically agonistic behavior. Postnatal CPF exposure increased maternal responsiveness toward pups in females. Mice of both sexes exposed to postnatal CPF showed reduced anxiety response in the plus-maze, an effect greater in females. Altogether, developmental exposure to CPF at doses that do not cause brain AChE inhibition induces long-term alterations in sex-specific behavior patterns of the mouse species. Late neonatal exposure on PNDs 11-14 was the most effective in causing behavioral changes. These findings support the hypothesis that developmental CPF may represent a risk factor for increased vulnerability to neurodevelopmental disorders in humans.     

Effects of repeated oral postnatal exposure to chlorpyrifos on cholinergic neurochemistry in developing rats.

The neurochemical effects of repeated postnatal exposure to chlorpyrifos (CPS) were studied in developing rats. Rats were gavaged daily from postnatal day (PND) 1-21 with CPS in corn oil starting at 1.5 mg/kg (low dosage group) and increasing gradually to 3 mg/kg and then to 6 mg/kg (high dosage group). Brain cholinesterase (ChE) activity was significantly inhibited on PND 6, 12, 22, and 30, with maximum inhibition on PND 6 of 49 and 59% and recovering to 18 and 33% on PND 30 in the low and high dosage groups, respectively. On PND 22 and 30, 94% or greater of the inhibited ChE could not be reactivated by the oxime TMB-4 in both treatment groups, indicating aging of the phosphorylated ChE. Total muscarinic acetylcholine receptors (mAChR) were reduced in a dose-related manner on PND 12 and 22, with substantial recovery by PND 30. M1/M3 mAChR were significantly reduced on PND 6 and 12 only in the high dosage group, and on PND 22 in both groups, while M2/M4 mAChR were reduced in the high dosage group on PND 22 and 30. On PND 30 choline acetyltransferase activity and vesicular acetylcholine transporter levels were decreased by 12 and 22%, respectively, only in the high dosage group. High-affinity choline transporter levels were decreased at all time points in the high dosage group and on PND 6, 22, and 30 in the low dosage group. The results presented here demonstrate that repeated postnatal exposures to CPS result in transient reductions of mAChR and more persistent alterations of presynaptic cholinergic neurons. In addition, the long-term reduction of brain ChE activity observed following repeated postnatal exposure to CPS is attributable to permanent inactivation or "aging" of the enzyme.     

高蛋白高脂肪饮食对普罗帕酮在大鼠体内药物动力学的影响

目的：研究高蛋白、高脂肪、高碳不化合物饮食大鼠的普罗帕酮（ＰＰＦ）药物动力学，以了解饮食因素对ＰＰＦ氧化代谢的影响。方法：采用ＨＰＬＣ法测定用药后不同时间血ＰＰＦ浓度，用３Ｐ８７程序处理数据，求得药物动力学参数。结果：与对照组相比，高蛋白饮食使ＰＰＦ Ｔ２／２β缩短，高蛋白和高脂记饮食均使之ＡＵＣ降低，ＣＬｓ增高。结论：高蛋白和高脂肪饮食加速大鼠ＰＰＦ的消除。     

The effect of quercetin on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rabbits

We have investigated the effect of quercetin on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rabbits. Pharmacokinetic parameters of verapamil and norverapamil were determined after the oral administration of verapamil (10 mg kg(-1)) to rabbits in the presence and absence of quercetin (5.0 and 15 mg kg(-1)). While co-administration of quercetin concurrently was not effective to enhance the oral exposure of verapamil, pretreatment of quercetin 30 min before verapamil administration significantly altered the pharmacokinetics of verapamil. Compared with the control group (given verapamil alone), the C(max) and AUC of verapamil increased approximately twofold in the rabbits pretreated with 15 mg kg(-1) quercetin. There was no significant change in T(max) and terminal plasma half-life (t(1/2)) of verapamil in the presence of quercetin. Consequently, absolute and relative bioavailability values of verapamil in the rabbits pretreated with quercetin were significantly higher (P < 0.05) than those from the control group. Metabolite-parent AUC ratio in the rabbits pretreated with quercetin decreased by twofold compared with the control group, implying that pretreatment of quercetin could be effective to inhibit the CYP3A4-mediated metabolism of verapamil. In conclusion, pretreatment of quercetin significantly enhanced the oral exposure of verapamil. This suggested that concomitant use of quercetin or a quercetin-containing dietary supplement with verapamil requires close monitoring for potential drug interaction.     

Effects of rifampicin on pharmacokinetics of isoniazid and its metabolite acetylhydrazine in rats.

After i.v. and i.p. injections of isoniazid (Iso) 40 mg.kg-1 to male Wistar rats, the plasma levels of Iso, acetylisoniazid (AcIso), and acetylhydrazine (AcHz) were determined by spectrophotometric method and gas chromatography. The results suggested that the pharmacokinetic behavior of Iso in rats belonged to a 2-compartment model. The plasma levels of AcHz in rifampicin (Rif 30 mg.kg-1)-pretreated rats were lowered vs the control (P < 0.05 or < 0.01). The T1/2 of AcHz was shortened by Rif (control group 3.3 h, Rif-pretreated group 1.4 h) after i.v. injection of AcHz 10 mg.kg-1 to rats and the results showed that AcHz was converted to its active metabolites quickly by increasing the oxidative elimination rate of AcHz, which is related to the higher incidence of liver necrosis caused by Iso and Rif in combination.     

Long-lasting reductions of ethanol drinking, enhanced ethanol-induced sedation, and decreased c-fos expression in the Edinger-Westphal nucleus in Wistar rats exposed to the organophosphate chlorpyrifos.

Intermittent or continuous exposure to a wide variety of chemically unrelated environmental pollutants might result in the development of multiple chemical intolerance and increased sensitivity to drugs of abuse. Interestingly, clinical evidence suggests that exposure to organophosphates might be linked to increased ethanol sensitivity and reduced voluntary consumption of ethanol-containing beverages in humans. The growing body of clinical and experimental evidence emerging in this new scientific field that bridges environmental health sciences, toxicology, and drug research calls for well-controlled studies aimed to analyze the nature of the neurobiological interactions of drugs and pollutants. Present study specifically evaluated neurobiological and behavioral responses to ethanol in Wistar rats that were previously exposed to the pesticide organophosphate chlorpyrifos (CPF). In agreement with clinical data, animals pretreated with a single injection of CPF showed long-lasting ethanol avoidance that was not secondary to altered gustatory processing or enhancement of the aversive properties of ethanol. Furthermore, CPF pretreatment increased ethanol-induced sedation without altering blood ethanol levels. An immunocytochemical assay revealed reduced c-fos expression in the Edinger-Westphal nucleus following CPF treatment, a critical brain area that has been implicated in ethanol intake and sedation. We hypothesize that CPF might modulate cellular mechanisms (decreased intracellular cAMP signaling, alpha-7-nicotinic receptors, and/or cerebral acetylcholinesterase inhibition) in neuronal pathways critically involved in neurobiological responses to ethanol.     

黄豆苷元对卡马西平及其代谢产物在大鼠体内药动学的影响

目的:研究黄豆苷元对卡马西平及其代谢产物10,11-环氧卡马西平(CBZ-E)在大鼠体内药动学的影响。方法:16只大鼠随机分为实验组和对照组,实验组大鼠连续10 d灌胃给予黄豆苷元100 mg.kg-1,对照组大鼠则灌胃给予等体积的生理盐水,两组大鼠第11天分别灌胃给予卡马西平10 mg.kg-1,于给药后不同时间点采血,采用HPLC法测定血浆中卡马西平及其代谢产物CBZ-E的浓度,计算药动学参数。结果:与对照组相比,实验组大鼠血浆中卡马西平的AUC0-24h、AUC0-∞、Cmax和t1/2显著增加(P<0.05),代谢产物CBZ-E的AUC0-24h、AUC0-∞和Cmax显著降低(P<0.05)。结论:黄豆苷元连续给药后改变了卡马西平在大鼠体内的药动学特征,可能与抑制CYP3A4的活性有关。     

A Physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for the organophosphate insecticide chlorpyrifos in rats and humans.

A PBPK/PD model was developed for the organophosphate insecticide chlorpyrifos (CPF) (O,O-diethyl-O-[3,5,6-trichloro-2-pyridyl]-phosphorothioate), and the major metabolites CPF-oxon and 3,5,6-trichloro-2-pyridinol (TCP) in rats and humans. This model integrates target tissue dosimetry and dynamic response (i.e., esterase inhibition) describing uptake, metabolism, and disposition of CPF, CPF-oxon, and TCP and the associated cholinesterase (ChE) inhibition kinetics in blood and tissues following acute and chronic oral and dermal exposure. To facilitate model development, single oral-dose pharmacokinetic studies were conducted in rats (0.5-100 mg/kg) and humans (0.5-2 mg/kg), and the kinetics of CPF, CPF-oxon, and TCP were determined, as well as the extent of blood (plasma/RBC) and brain (rats only) ChE inhibition. In blood, the concentration of analytes followed the order TCP > CPF > CPF-oxon; in humans CPF-oxon was not quantifiable. Simulations were compared against experimental data and previously published studies in rats and humans. The model was utilized to quantitatively compare dosimetry and dynamic response between rats and humans over a range of CPF doses. The time course of CPF and TCP in both species was linear over the dose range evaluated, and the model reasonably simulated the dose-dependent inhibition of plasma ChE, RBC acetylcholinesterase (AChE), and brain (rat only) AChE. Model simulations suggest that rats exhibit greater metabolism of CPF to CPF-oxon than humans do, and that the depletion of nontarget B-esterase is associated with a nonlinear, dose-dependent increase in CPF-oxon blood and brain concentration. This CPF PBPK/PD model quantitatively estimates target tissue dosimetry and AChE inhibition and is a strong framework for further organophosphate (OP) model development and for refining a biologically based risk assessment for exposure to CPF under a variety of scenarios.     

曲克芦丁及其代谢产物在大鼠体内的排泄动力学研究

目的研究曲克芦丁及其代谢产物在大鼠体内的排泄情况。方法大鼠腹腔注射曲克芦丁,收集尿液、粪便和胆汁样品,应用 HPLC方法测定曲克芦丁在大鼠尿液、粪便和胆汁样品的含量,测定曲克芦丁代谢产物在大鼠粪便中的含量。结果曲克芦丁在大鼠尿液、粪便和胆汁中的累积排泄率分别为( 16.17±10.28)%、(0.54±0.47)%和( 58.94±13.37)%。与此同时,粪便中约有( 22.69±12.48)%的代谢产物曲克芦丁苷元生成。结论曲克芦丁主要通过胆汁进行排泄,以原型和代谢产物的形式排出体外。