scholarly journals The Effects of Formaldehyde on Cytochrome P450 Isoform Activity in Rats

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Min Xu ◽  
Huaqiao Tang ◽  
Qian Rong ◽  
Yuanli Zhang ◽  
Yinglun Li ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Control Group ◽  
High Dose ◽  
Blood Samples ◽  
Time Points ◽  
Indoor Pollutant ◽  
Carcinogenic Effects

Formaldehyde (FA) is an occupational and indoor pollutant. Long-term exposure to FA can irritate the respiratory mucosa, with potential carcinogenic effects on the airways. The effects of acute FA poisoning on the activities of CYP450 isoforms CYP1A2, CYP2C11, CYP2E1, and CYP3A2 were assessed by determining changes in the pharmacokinetic parameters of the probe drugs phenacetin, tolbutamide, chlorzoxazone, and testosterone, respectively. Rats were randomly divided into three groups: control, low FA dose (exposure to 110 ppm for 2 h for 3 days), and high FA dose (exposure to 220 ppm for 2 h for 3 days). A mixture of the four probe drugs was injected into rats and blood samples were taken at a series of time points. Plasma concentrations of the probe drugs were measured by HPLC. The pharmacokinetic parameters t1/2, AUC(0-t), and Cmax of tolbutamide, chlorzoxazone, and testosterone increased significantly in the high dose versus control group (P<0.05), whereas the CL of chlorzoxazone and testosterone decreased significantly (P<0.05). However, t1/2, AUC(0-t), and Cmax of phenacetin decreased significantly (P<0.05), whereas the CL of phenacetin increased significantly (P<0.05) compared to controls. Thus, acute FA poisoning suppressed the activities of CYP2C11, CYP2E1, and CYP3A2 and induced the activity of CYP1A2 in rats. And the change of CYP450 activity caused by acute FA poisoning may be associated with FA potential carcinogenic effects on the airways.

183 EFFECTS OF LONG-TERM NUTRITIONAL RESTRICTION ON PREOVULATORY LUTEINIZING HORMONE SURGE, LEPTIN, AND LUTEAL PHASE IN LLAMAS (LAMA GLAMA)

2013 ◽  
Vol 25 (1) ◽  
pp. 240
Author(s):  
M. C. Norambuena ◽  
M. Silva ◽  
F. Urra ◽  
C. Ulloa-Leal ◽  
C. Letelier ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Transvaginal Ultrasound ◽  
Plasma Concentrations ◽  
Maximum Diameter ◽  
Control Group ◽  
Blood Samples ◽  
Dependent Variables ◽  
Nutritional Restriction ◽  
Plasma Leptin

The aim of the study was to determine the effect of long-term energy restriction on preovulatory LH surge and luteal phase in llamas. Mature nonlactating, nonpregnant, female llamas (n = 16) were assigned randomly to the following groups: (1) llamas received Ballica sp. hay ad libitum and 300 g d–1 of commercial concentrate (control group, n = 8, BCS = 3.9) or (2) llamas were fed the same feed but the amount was progressively reduced from 70% to 40% of their maintenance energy requirement (MER) for a period of 87 days, until the final BCS was 2.5 (restricted group, n = 8). After 2 months and 21 days of 40% MER diet, ovarian follicular wave emergence was synchronized by transvaginal ultrasound-guided ablation of follicles ≥5 mm in diameter using a 17-ga needle attached to a 5-MHz convex-array transducer. Ten days after follicle ablation (Day 0), llamas were given an i.m. dose of 50 µg of gonadorelin acetate to induce ovulation. Frequent blood samples were taken every 30 min for 6 h and every 15 min for 1 h for plasma LH and leptin concentration measurements, respectively, immediately after treatment. Llamas were examined daily by transrectal ultrasonography for 20 days to record serial changes in the CL diameter. In addition, blood samples were taken every 2 days from Day 0 to 16 to determine plasma concentrations of leptin and progesterone. Discrete dependent variables were compared between groups by Student t-tests and continuous dependent variables were analysed by analyses of variance with repeated-measures. There was an effect of time on plasma LH concentration (P ≤ 0.001), but not an effect of group (P = 0.1) or interaction (P = 0.6) after gonadorelin acetate treatment. Plasma leptin concentration was lower in llamas from the restricted than that of the control group after gonadorelin treatment [effect of time, group (P ≤ 0.01), and interaction (P ≤ 0.01)]. The maximum diameter of the CL and plasma progesterone concentration were lower in the restricted than in the control group, and both variables were affected by group (P ≤ 0.01, P ≤ 0.02), and day (P ≤ 0.001, P ≤ 0.001, respectively). Plasma leptin concentration was lower in the restricted than that of the control group during the entire experiment. In conclusion, long-term nutritional restriction affected negatively CL diameter, progesterone secretion, and leptin plasma concentration in llamas. The differential response of leptin to gonadorelin acetate treatment could reflect a subfertlity-nutritional induced problem related with steroidogenesis, oocyte quality, ovulation, and early embryo development processes. Research supported by Postdoctoral Fondecyt N° 3110095.

scholarly journals Evaluating the effect of Ganoderma lucidum polysaccharides on five cytochrome P450 isozymes with cocktail probe drugs in rats by LC–MS/MS

2019 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Cytochrome P450 ◽  
Ganoderma Lucidum ◽  
Low Dose ◽  
Antioxidant Activities ◽  
Plasma Concentrations ◽  
Control Group ◽  
High Dose ◽  
Positive Effects ◽  
Ganoderma Lucidum Polysaccharides ◽  
Tandem Mass Spectrometric

Ganoderma lucidum polysaccharides (GLPs) are commonly used as health-promoting medicine and dietary supplement due to the positive effects in immune modulation, antitumor and antioxidant activities. However, whether GLPs executes other uncharacterized effects is largely unclear. The rats were pre-primed with GLPs and then administrated with canonical “cocktail probes” of cytochrome P450 (CYP450) isozymes including caffeine, tolbutamide, dextromethorphan, omeprazole, and midazolam. The plasma concentrations of probes at each indicated time point were simultaneously detected using the designed high-performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) method. The results suggested that GLPs could increase the accumulated levels of caffeine, tolbutamide and midazolam in plasma as compared to control group. Besides, GLPs reduced the concentration of dextromethorphan in blood at high dose, while elevated it at low dose. GLPs could inhibit the activities of CYP1A2, and CYP3A4, additionally; GLPs at low dose suppressed the activity of CYP2D6, which demonstrated that drugs co-administrated with GLPs might require strictly evaluating the dose relation.

scholarly journals Influences of Anlotinib on Cytochrome P450 Enzymes in Rats Using a Cocktail Method

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Sun ◽  
Zhe Wang ◽  
Ruimin Chen ◽  
Chengke Huang ◽  
Rui Sun ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Oral Administration ◽  
Inductive Effect ◽  
Saline Control ◽  
Control Group ◽  
Cytochrome P450 Enzymes ◽  
Saline Control Group ◽  
Blood Samples ◽  
Time Points

The present study aimed to investigate the effect of anlotinib (AL3818) on pharmacokinetics of cytochrome P450 (CYP) enzymes (CYP1A2, CYP2C6, CYP2D1, CYP2D2, and CYP3A1/2) by using five cocktail probe drugs in vivo. After pretreatment for 7 days with anlotinib (treatment group) or saline (control group) by oral administration, probe drugs phenacetin, tolbutamide, omeprazole, metoprolol, and midazolam were administered to rats by oral administration. Blood samples were obtained at a series of time-points and the concentrations of five probe drugs in plasma were determined by a UHPLC-MS/MS method. The results showed that treatment with anlotinib had no significant effect on rat CYP1A2, CYP2D2, and CYP2C6. However, anlotinib had a significant inductive effect on CYP2D1 and CYP3A1/2. Therefore, caution is needed during the concomitant use of anlotinib with other drugs metabolized by CYP2D1 and CYP3A1/2 because of potential drug-anlotinib interactions.

scholarly journals Impact of weight loss achieved through a multidisciplinary intervention on appetite in patients with severe obesity

2018 ◽  
Vol 315 (1) ◽  
pp. E91-E98 ◽  
Author(s):  
S. R. Coutinho ◽  
J. F. Rehfeld ◽  
J. J. Holst ◽  
B. Kulseng ◽  
C. Martins
Keyword(s):  
Weight Loss ◽  
Severe Obesity ◽  
Peptide Yy ◽  
Plasma Concentrations ◽  
Cardiovascular Fitness ◽  
Ghrelin Concentration ◽  
Time Points ◽  
Diet And Exercise ◽  
The Impact

The impact of lifestyle-induced weight loss (WL) on appetite in patients with obesity remains controversial. This study aimed to assess the short- and long-term impact of WL achieved by diet and exercise on appetite in patients with obesity. Thirty-five (22 females) adults with severe obesity (body mass index: 42.5 ± 5.0 kg/m2) underwent a 2-yr WL program focusing on diet and exercise. Body weight (BW), cardiovascular fitness (V̇o2max), appetite feelings, and plasma concentrations of insulin, active ghrelin (AG), glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and cholecystokinin (CCK), in the fasting and postprandial states, were measured at baseline (B), week 4 (W4), and 1 and 2 yr (and average values for all fasting and postprandial time points computed). BW was significantly reduced and V̇o2max(ml·kg−1·min−1) increased at all time points compared with B (3.5, 8.1, and 8.4% WL and 7, 11, and 8% increase at W4 and 1 and 2 yr, respectively). Basal hunger and average hunger and desire to eat were significantly increased at 1 and 2 yr. Basal fullness was significantly increased at W4, and average ratings were reduced at 1 yr. Average AG and PYY were significantly increased, and insulin was reduced, at all time points compared with B. Average GLP-1 was reduced at W4, and CCK was increased at 2 yr. After lifestyle-induced WL, patients with severe obesity will, therefore, have to deal with increased hunger in the long term. In conclusion, sustained WL at 2 yr achieved with diet and exercise is associated with increased hunger feelings and ghrelin concentration but also increased postprandial concentrations of satiety hormones.

scholarly journals Evaluation of the BDNF, NGF, NT3 and NT4 Genes Expressions in the Brains of Neonatal Mice with Hypothyroidism

2017 ◽  
Vol 7 (1) ◽  
pp. 171
Author(s):  
Hamid Reza Adeli Bhroz ◽  
Kazem Parivar ◽  
Iraj Amiri ◽  
Nasim Hayati Roodbari
Keyword(s):  
Dose Group ◽  
Low Dose ◽  
Pure Water ◽  
Intervention Group ◽  
Control Group ◽  
High Dose ◽  
Endocrine Glands ◽  
Blood Samples ◽  
High Doses ◽  
The Brain

Background and Aim: Thyroid is one of the endocrine glands, (T3 and T4) play a significant role in the development of prenatal brain and the following stages. The study aimed to evaluate the effect of hypothyroidism on the amount of expression of NT4, NT3, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in brain of one-day rat neonates with hypothyroidism.Materials and Methods: In total, 25 mature mice of Albino NMRI race were selected after mating, divided into three group, control, as well as low-dose and high-dose intervention groups. Samples of the control group received pure water during pregnancy, whereas subjects of the intervention group with low and high doses of the medication were administered with 20 mg and 100 mg methimazole powder (dissolved in 100 cc water), respectively. After child delivery, blood samples were obtained from mother mice to determine the level of T3 and T4 in blood serum. Following that, the brain of one-day mice were removed by surgery and assessed to determine the amount of expression of NT4, NT3, NGF and BDNF using the complete kit of RT-PCR.Results: Levels of T4 and T3 in the control group were 28 ug/dl and 1.59 ug/dl, respectively. In the low-dose intervention group, the amounts of the mentioned hormones were 8 ug/dl and 0.85 ug/dl, significantly, indicating a significant reduction in the expression of NT4, NT3, NGF and BDNF genes, compared to the control group. Moreover, T4 and T3 were 6 ug/dl and 0.79 ug/dl in the high-dose group, respectively, conveying a significant decrease in the expression of NT4, NT3, NGF and BDNF genes, compared to the control group (P<0.05).

Enlargement of cerebrospinal fluid spaces in long-term benzodiazepine abusers

1987 ◽  
Vol 17 (4) ◽  
pp. 869-873 ◽  
Author(s):  
C. Schmauss ◽  
J.-C. Krieg
Keyword(s):  
Low Dose ◽  
Matched Control ◽  
Control Group ◽  
High Dose ◽  
Withdrawal Therapy ◽  
The Mean ◽  
Dose Dependent ◽  
Dose Dependent Effect ◽  
Age And Sex

SynopsisIn 17 benzodiazepine (BDZ) dependent in-patients a CT scan was performed before initiation of withdrawal therapy. The evaluation of the ventricular to brain ratio (VBR) by standardized and computerized measurements revealed significantly higher mean VBRs for both high-and low-dose BDZ-dependent patients compared to the mean VBR of an age- and sex-matched control group. In addition, the mean VBR of high-dose BDZ-dependent patients (N = 8) was significantly higher than the mean VBR of low-dose BDZ-dependent patients (N = 9). This difference could not be accounted for by the age of the patients or duration of BDZ-dependency and, therefore, suggests a dose-dependent effect of BDZs on the enlargement of internal CSF-spaces. On the other hand, higher values for the width of external CSF-spaces were found to be related to increasing age of the patients and duration of BDZ-dependency.

Pharmacokinetic Evaluation of anti-HIV Drug Interactions: Effect of Zidovudine on 2′-3′-Dideoxyinosine Kinetics in Monkeys

1993 ◽  
Vol 4 (3) ◽  
pp. 155-159 ◽  
Author(s):  
M. Qian ◽  
A. R. Swagler ◽  
M. Mehta ◽  
C.T. Vishwanathan ◽  
J. M. Gallo
Keyword(s):  
Dose Group ◽  
Plasma Concentrations ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
High Dose ◽  
Combination Regimen ◽  
Time Profiles ◽  
Elimination Half ◽  
Constant Rate ◽  
Rate Infusion

The current investigation was conducted to determine if zidovudine (AZT) altered the pharmacokinetics of dideoxyinosine (ddl) in non-hurnan primates, an appropriate animal model for AZT and ddl pharmacokinetics in human. Each of nine animals received 20 mg kg−1 of ddl intravenously in the absence and presence of two different dosage regimens of AZT. For each combination regimen, AZT was administered as a combined i.v. bolus-constant rate infusion regimen for 30 min that produced AZT plasma concentrations of about 4 μg ml−1 in six animals (low dose group) and 11 μg ml−1 in three others (high dose group). Serial blood samples were collected, and pharmacokinetic parameters for ddl were calculated based on plasma ddl concentrations measured by HPLC techniques. The pharmacokinetics of ddl given alone in the first phase of the low ( n = 6) and high ( n = 6) dose AZT groups, resulted in a mean elimination half-life 1.54 and 1.9h, a mean total clearance of 0.62 and 0.731 h−1 kg−1, and a mean steady state volume of distribution of 1.02 and 0.891 kg−1, respectively. Following combined ddl and AZT administrations, in both the low and high dose AZT groups, plasma concentration-time profiles of ddl were similar for each monkey, and no statistical differences were observed in the pharmacokinetic parameters compared to those obtained when ddl was given alone. The fact that AZT does not alter the pharmacokinetics of ddl at the range of AZT dose studied provides a basis for rational dosage design for combined ddl and AZT treatments in HIV infection.

Effect of human recombinant superoxide dismutase on canine myocardial infarction

1990 ◽  
Vol 258 (2) ◽  
pp. H369-H380 ◽  
Author(s):  
B. S. Patel ◽  
M. O. Jeroudi ◽  
P. G. O'Neill ◽  
R. Roberts ◽  
R. Bolli
Keyword(s):  
Superoxide Dismutase ◽  
Infarct Size ◽  
Low Dose ◽  
Coronary Occlusion ◽  
Plasma Concentrations ◽  
Control Group ◽  
High Dose ◽  
Collateral Flow ◽  
Tetrazolium Chloride ◽  
Arterial Blood

To determine whether human recombinant superoxide dismutase (h-SOD) produces sustained reduction of infarct size, anesthetized dogs underwent a 2-h coronary occlusion followed by either 48 or 4 h of reperfusion. In the 48-h study, dogs were randomized to three intravenous treatments: 1) “low-dose” h-SOD (2 mg/kg bolus 2 min before reperfusion followed by 4 mg/kg over 45 min), 2) “high-dose” h-SOD (8 mg/kg bolus 2 min before reperfusion followed by 8 mg/kg over 45 min), or 3) equivalent volumes of saline. In the 4-h study, dogs were randomized to high-dose h-SOD or saline. Occluded bed size was measured by postmortem perfusion and infarct size by triphenyl tetrazolium chloride staining and planimetry. Investigators performing the study and measuring infarct size were blinded to the treatment given. High plasma concentrations of h-SOD were present in the arterial blood of treated dogs in the early phase of reperfusion (greater than 60 and greater than 180 micrograms/ml in low- and high-dose groups, respectively). In both studies, control and treated groups were similar with respect to occluded bed size, collateral blood flow, and rate-pressure product during ischemia. In the 48-h study, infarct size, expressed as percent of occluded bed size, was 41.3 +/- 7.6% (mean +/- SE) in the control group, 37.1 +/- 7.2% in the low-dose h-SOD group, and 48.0 +/- 7.1% in the high-dose h-SOD group. In the 4-h study, infarct size was 30.6 +/- 4.9% in the control group and 31.5 +/- 9.6% in the high-dose h-SOD group. Analysis of the flow-infarct relationships confirmed that h-SOD did not reduce infarct size at any level of collateral flow in either the 48- or 4-h study. Recovery of regional myocardial function after reperfusion was also unaffected by h-SOD in both studies. Thus in this randomized blinded study, large doses of h-SOD given at the time of reperfusion failed to limit infarct size or enhance recovery of function, both early (4 h) and late (48 h) after reperfusion following a 2-h coronary occlusion.

scholarly journals Herb-Drug Interaction: Effects of Relinqing® Granule on the Pharmacokinetics of Ciprofloxacin, Sulfamethoxazole, and Trimethoprim in Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Yuan Lu ◽  
ZiPeng Gong ◽  
YuMin Xie ◽  
Jie Pan ◽  
Jia Sun ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Pharmacokinetic Parameters ◽  
Control Group ◽  
Urinary System ◽  
Blood Samples ◽  
Sd Rats ◽  
Chinese Patent ◽  
Group 2 ◽  
And Control ◽  
Group 1

Relinqing granule (RLQ) is the best-selling Chinese patent drug for treatment of urinary system diseases. In this study, the effects of RLQ on the pharmacokinetics of ciprofloxacin, sulfamethoxazole, and trimethoprim in SD rats were investigated. Rats were randomly divided into control group 1, control group 2, RLQ group 1, and RLQ group 2. RLQ group 1 and RLQ group 2 were treated orally with RLQ for 7 days, and rats were treated with the same volume of water in control group 1 and control group 2. Then, RLQ group 1 and control group 1 were given intragastrically ciprofloxacin on day 8, while RLQ group 2 and control group 2 were given intragastrically sulfamethoxazole and trimethoprim on day 8. Blood samples were collected and determined. There was no significant influence of pharmacokinetic parameters of trimethoprim on two groups. But some pharmacokinetic parameters of ciprofloxacin and sulfamethoxazole in RLQ pretreated rats were evidently altered (P < 0.05), which indicated that absorption of ciprofloxacin and sulfamethoxazole in RLQ pretreated rats was significantly affected. It indicated the coadministration of RLQ would have an influence on the efficacy of ciprofloxacin and sulfamethoxazole, and the doses of ciprofloxacin tablet and compound sulfamethoxazole tablet need adjustment.

Impact of polymorphisms in the CYP2B6 gene on the pharmacokinetics of cyclophosphamide and thiotepa

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 13062-13062
Author(s):  
C. Ekhart ◽  
A. Huitema ◽  
S. Rodenhuis ◽  
J. H. Beijnen
Keyword(s):  
A Priori ◽  
Plasma Concentrations ◽  
Hepatic Clearance ◽  
High Dose Chemotherapy ◽  
Pharmacokinetic Parameters ◽  
High Dose ◽  
Severe Toxicity ◽  
Active Metabolites ◽  
Increased Risk ◽  
Cyp2b6 Gene

13062 Background: Cyclophosphamide and thiotepa are frequently used simultaneously as part of high dose chemotherapy regimens for solid tumours. Although generally well tolerated, severe toxicity may occur. Relationships between pharmacokinetics and toxicity have been identified. Cyclophosphamide and thiotepa are both metabolised by cytochrome P450 (CYP)enzymes, resulting in the active metabolites 4-hydroxycyclophosphamide and tepa respectively. CYP2B6 and CYP3A4 are the major metabolising isozymes for both compounds. In this study we investigated the relationship between polymorphisms of the CYP2B6 gene and the hepatic clearance of cyclophosphamide and thiotepa in order to identify a priori patients at risk for severe toxicity. Methods: CYP2B6*2 (C64T) and variants A785G, C1459T and G516T were identified by PCR and sequencing samples from 82 patients receiving a high dose regimen consisting of cyclophosphamide (4–6 g/m2), thiotepa (320–480 mg/m2) and carboplatin (AUC 13–20 mg*min/ml). Plasma concentrations of thiotepa, cyclophosphamide and metabolites were determined using a validated LC-MS/MS method. Individual pharmacokinetic parameters were obtained using nonlinear mixed effects modelling. Results: A total of 82 patients was included. Not all data of the various variants were available. All investigated variants had an allele frequency of > 3% in the population. While 94% of the patients had the wildtype genotype for CYP2B6*2, 6% were heterozygous. Heterozygous patients for *2 had a lower hepatic clearance of thiotepa compared to wildtype patients (11.7 l*h−1 vs 14.4 l*h−1) (P=0.03). All other allelic variants investigated showed no effect on either hepatic clearance of thiotepa or cyclophosphamide. Conclusions: This study demonstrates that the hepatic clearance of thiotepa is reduced in patients with a heterozygous CYP2B6*2 genotype. Patients with this genotype may have an increased exposure to thiotepa and may, therefore, be at increased risk for organ toxicity. No significant financial relationships to disclose.

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