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Biodisposition of CP31398 in rat toxicology and efficacy studies
S106
Abstracts / Toxicology Letters 196S (2010) S37–S351
P107-002 Biodisposition of CP31398 in rat toxicology and efficacy studies I.M. Kapetanovic 1 , M. Muzzio 2 , D.L. Mccormick 2 , A. Mohammed 3 , C.V. Rao 3 , L. Kopelovich 1 1
National Cancer Institute, NIH, 2 IIT Research Institute, 3 The University of Oklahoma Health Sciences Center More than 50% of human cancers demonstrate reduced or lost function of the p53 tumor suppressor gene. Restoration or stabilization of p53 function presents an attractive strategy for cancer prevention and therapy. The styrylquinazoline, CP31398 (N -[2-[(E)-2-(4-methoxyphenyl)ethenyl]quinazolin-4-yl]N,N-dimethylpropane-1,3-diamine hydrochloride), demonstrates chemopreventive efficacy in animal models for skin and colon carcinogenesis, and is a candidate for clinical trials in cancer prevention. Pharmacokinetic evaluations of CP31398 were performed as part of preclinical toxicology and efficacy studies in male rats. Plasma levels of CP31398 were quantitated via tandem MS/HPLC (LC–MS–MS), and metabolites were quantitated and identified using quadrupole time-of-flight (Q-TOF) LC–MS. In a 14-day toxicity study using oral (gavage) administration, the No-Observed-Adverse-Effect-Level (NOAEL) for CP31398 was 50 mg/kg/day. After a single gavage dose of 100 mg/kg, CP31398 showed an elimination half-life of 37 h and apparent clearance of 18.3 L/h/kg. After 7 daily gavage doses of CP31398 (25, 50, or 100 mg/kg/day), average steady-state plasma concentrations [Css (Cmin , Cmax )] were 33.3 (27.3, 55.8) ng/ml at the low dose, 55.8 (40.3, 95.6) ng/ml at the mid dose, and 87.1 (65.7, 122.3) ng/ml at the high dose. In an efficacy study using dietary administration of CP31398 (150 and 300 mg/kg diet), plasma drug concentrations [mean (SD)] after 31 weeks of exposure were 8.7 (2.0) ng/ml at the low dose and 20.8 (8.8) ng/ml at the high dose. The low and high doses of CP31398 reduced colon cancer incidence by 30 and 44% versus dietary control, and reduced cancer multiplicity by 51 and 65% versus control. Prevalent metabolites were N-desmethyl, O-desmethyl, and hydroxylated, with lower levels of didesmethyl and O-desmethyl hydroxyl. Levels of each metabolite were 10% or less of the parent, and lower levels were seen in the efficacy study (dietary administration) than in the toxicology study (gavage administration). Conjugated metabolites were not detectable. doi:10.1016/j.toxlet.2010.03.377
P107-003 Biochemical toxicity of phenol in treated mice A. Louei Monfared School of Veterinary Medicine, University of Ilam, Ilam, Iran Aims: The aim of this study was to investigate the dose-related effects of phenol on the biochemical enzymes of sera included serum creatinine (CRT) and blood urea nitrogen (BUN) levels in kidney and liver. Methods: A total of 80 female Balb/C mice were randomly subdivided into control group and 3 study groups. Control group was administered of tap water solution alone by gavage. Study groups received 80, 180 and 320 mg/kg of phenol, by gavage. The animals were observed for 14 days, and were euthanized by chloroform and dissected then the heart blood was sampled and collected in heparinized tubes (Becton-Dickinson Franklin Lakes, NJ) from. Blood was centrifuged at 5000 rpm for 10 min. The serum was separated
and stored at −70 ◦ C and then values of CRT and BUN were evaluated. Results: There was a rise in serum levels of BUN and CRT at the end of ten days in the mice exposed to 180 and 320 mg/kg phenol, but no significant differences were found when compared with the control group and the mice exposed to 80 mg/kg phenol. However, BUN and CRT levels at ten days were markedly elevated (P < 0.05) in the mice exposed to 180 and 320 mg/kg phenol compared to controls with normal renal function. Conclusion: These results indicate the hurtful effect of phenol on kidney. doi:10.1016/j.toxlet.2010.03.378
P107-004 Testosterone hydroxylases in evaluating induction of cytochrome P450 isoenzymes by pyrethroids Type II deltamethrin and cyfluthrin M.A. Martínez, V. Castellano, E. Ramos, I. Ares, M. Martínez, M.R. ˜ Martínez-Larranaga, A. Anadón. Universidad Complutense de Madrid, Spain Cytochrome P450s are Phase I enzymes that metabolize endogenous as well as exogenous compounds. They play a key role in the metabolic activation of a number of compounds. There is relatively little information about the effects of pyrethroids on hepatic microsomal drug-metabolizing function. The objective of the present study is to investigate the effect of the pyrethroids Type II deltametrin and cyfluthrin on hepatic microsomal testosterone hydroxylase activities, which are closely associated with the P4502A, P4502B and P4503A subfamilies of hemoproteins. Groups of 6 male Wistar rats weighing 180 g were treated with deltamethrin (single daily oral dose of 8 mg/kg for 6 days) and cyfluthrin (single daily oral dose of 20 mg/kg for 6 days). Control animals received orally corn oil. Pyrethroid-treated and control animals were sacrificed 24 h after the last administration and livers were removed. The livers were individually homogenized and microsomal pellets prepared and stored at −90 ◦ C prior to use. The microsomal hydroxylation of testosterone was determined. Testosterone metabolites were analyzed by HPLC assay utilizing a reverse phase column and a mobile phase consisting of a methanol: water: acetonitrile gradient. Column effluents were monitorized at 254 nm. Metabolites were quantitated by comparison of their peak areas with those of reference standards. Deltamethrin and cyfluthrin induce some members of P4502A, P4502B and P4503A subfamilies. Deltamethrin and cyfluthrin treatment resulted in an increase significantly (p < 0.01) in the formation of 6-betahydroxytestosterone (78% and 86%) 7-alfa-hydroxytestosterone (63% and 53%) and 16-beta-hydroxytestosterone (143% and 134%), respectively. The findings of this study strongly suggest that induction of cytochrome P450 enzymes is a very important issue in risk assessment of these insecticides. This work has been supported by projects No. CCG07-UCM/AGR-2618 & Consolider-Ingenio 2010 No. CSD2007-063 (MEC), Spain. doi:10.1016/j.toxlet.2010.03.379
Abstracts / Toxicology Letters 196S (2010) S37–S351
P107-002 Biodisposition of CP31398 in rat toxicology and efficacy studies I.M. Kapetanovic 1 , M. Muzzio 2 , D.L. Mccormick 2 , A. Mohammed 3 , C.V. Rao 3 , L. Kopelovich 1 1
National Cancer Institute, NIH, 2 IIT Research Institute, 3 The University of Oklahoma Health Sciences Center More than 50% of human cancers demonstrate reduced or lost function of the p53 tumor suppressor gene. Restoration or stabilization of p53 function presents an attractive strategy for cancer prevention and therapy. The styrylquinazoline, CP31398 (N -[2-[(E)-2-(4-methoxyphenyl)ethenyl]quinazolin-4-yl]N,N-dimethylpropane-1,3-diamine hydrochloride), demonstrates chemopreventive efficacy in animal models for skin and colon carcinogenesis, and is a candidate for clinical trials in cancer prevention. Pharmacokinetic evaluations of CP31398 were performed as part of preclinical toxicology and efficacy studies in male rats. Plasma levels of CP31398 were quantitated via tandem MS/HPLC (LC–MS–MS), and metabolites were quantitated and identified using quadrupole time-of-flight (Q-TOF) LC–MS. In a 14-day toxicity study using oral (gavage) administration, the No-Observed-Adverse-Effect-Level (NOAEL) for CP31398 was 50 mg/kg/day. After a single gavage dose of 100 mg/kg, CP31398 showed an elimination half-life of 37 h and apparent clearance of 18.3 L/h/kg. After 7 daily gavage doses of CP31398 (25, 50, or 100 mg/kg/day), average steady-state plasma concentrations [Css (Cmin , Cmax )] were 33.3 (27.3, 55.8) ng/ml at the low dose, 55.8 (40.3, 95.6) ng/ml at the mid dose, and 87.1 (65.7, 122.3) ng/ml at the high dose. In an efficacy study using dietary administration of CP31398 (150 and 300 mg/kg diet), plasma drug concentrations [mean (SD)] after 31 weeks of exposure were 8.7 (2.0) ng/ml at the low dose and 20.8 (8.8) ng/ml at the high dose. The low and high doses of CP31398 reduced colon cancer incidence by 30 and 44% versus dietary control, and reduced cancer multiplicity by 51 and 65% versus control. Prevalent metabolites were N-desmethyl, O-desmethyl, and hydroxylated, with lower levels of didesmethyl and O-desmethyl hydroxyl. Levels of each metabolite were 10% or less of the parent, and lower levels were seen in the efficacy study (dietary administration) than in the toxicology study (gavage administration). Conjugated metabolites were not detectable. doi:10.1016/j.toxlet.2010.03.377
P107-003 Biochemical toxicity of phenol in treated mice A. Louei Monfared School of Veterinary Medicine, University of Ilam, Ilam, Iran Aims: The aim of this study was to investigate the dose-related effects of phenol on the biochemical enzymes of sera included serum creatinine (CRT) and blood urea nitrogen (BUN) levels in kidney and liver. Methods: A total of 80 female Balb/C mice were randomly subdivided into control group and 3 study groups. Control group was administered of tap water solution alone by gavage. Study groups received 80, 180 and 320 mg/kg of phenol, by gavage. The animals were observed for 14 days, and were euthanized by chloroform and dissected then the heart blood was sampled and collected in heparinized tubes (Becton-Dickinson Franklin Lakes, NJ) from. Blood was centrifuged at 5000 rpm for 10 min. The serum was separated
and stored at −70 ◦ C and then values of CRT and BUN were evaluated. Results: There was a rise in serum levels of BUN and CRT at the end of ten days in the mice exposed to 180 and 320 mg/kg phenol, but no significant differences were found when compared with the control group and the mice exposed to 80 mg/kg phenol. However, BUN and CRT levels at ten days were markedly elevated (P < 0.05) in the mice exposed to 180 and 320 mg/kg phenol compared to controls with normal renal function. Conclusion: These results indicate the hurtful effect of phenol on kidney. doi:10.1016/j.toxlet.2010.03.378
P107-004 Testosterone hydroxylases in evaluating induction of cytochrome P450 isoenzymes by pyrethroids Type II deltamethrin and cyfluthrin M.A. Martínez, V. Castellano, E. Ramos, I. Ares, M. Martínez, M.R. ˜ Martínez-Larranaga, A. Anadón. Universidad Complutense de Madrid, Spain Cytochrome P450s are Phase I enzymes that metabolize endogenous as well as exogenous compounds. They play a key role in the metabolic activation of a number of compounds. There is relatively little information about the effects of pyrethroids on hepatic microsomal drug-metabolizing function. The objective of the present study is to investigate the effect of the pyrethroids Type II deltametrin and cyfluthrin on hepatic microsomal testosterone hydroxylase activities, which are closely associated with the P4502A, P4502B and P4503A subfamilies of hemoproteins. Groups of 6 male Wistar rats weighing 180 g were treated with deltamethrin (single daily oral dose of 8 mg/kg for 6 days) and cyfluthrin (single daily oral dose of 20 mg/kg for 6 days). Control animals received orally corn oil. Pyrethroid-treated and control animals were sacrificed 24 h after the last administration and livers were removed. The livers were individually homogenized and microsomal pellets prepared and stored at −90 ◦ C prior to use. The microsomal hydroxylation of testosterone was determined. Testosterone metabolites were analyzed by HPLC assay utilizing a reverse phase column and a mobile phase consisting of a methanol: water: acetonitrile gradient. Column effluents were monitorized at 254 nm. Metabolites were quantitated by comparison of their peak areas with those of reference standards. Deltamethrin and cyfluthrin induce some members of P4502A, P4502B and P4503A subfamilies. Deltamethrin and cyfluthrin treatment resulted in an increase significantly (p < 0.01) in the formation of 6-betahydroxytestosterone (78% and 86%) 7-alfa-hydroxytestosterone (63% and 53%) and 16-beta-hydroxytestosterone (143% and 134%), respectively. The findings of this study strongly suggest that induction of cytochrome P450 enzymes is a very important issue in risk assessment of these insecticides. This work has been supported by projects No. CCG07-UCM/AGR-2618 & Consolider-Ingenio 2010 No. CSD2007-063 (MEC), Spain. doi:10.1016/j.toxlet.2010.03.379