Publications by authors named "Shirin Pournourmohammadi"

16 Publications

  • Page 1 of 1

Tolerability and Safety Profile of a New Brand-Generic Product of Glatiramer Acetate in Iranian Patients with Relapsing-Remitting Multiple Sclerosis: An Observational Cohort Study.

Curr Ther Res Clin Exp 2018 28;88:47-51. Epub 2018 May 28.

Neurology Department, Tehran University of Medical Sciences, Amiralam Hospital, Tehran, Iran.

Background: The aim of this study was to evaluate the safety, tolerability, and efficacy of a brand-generic glatiramer acetate product in patients with relapsing-remitting multiple sclerosis over a 12-month period. A noninterventional cohort study was conducted on 185 patients. The patients had a confirmed and documented diagnosis of relapsing-remitting multiple sclerosis as defined by the Revised McDonald Criteria (2010), were ambulatory with a Kurtzke Expanded Disability Status Scale score of 0 to 5.5, and their treatment by glatiramer acetate 40 mg/mL was just started.

Methods: Adverse drug reactions, relapse rate, magnetic resonance imaging parameters, and Expanded Disability Status Scale score were evaluated over 1 year.

Results: Of 185 enrolled patients from 21 different cities, 170 completed the study. The mean (SD) Expanded Disability Status Scale score was 1.97 (0.75) at the time of screening. The mean age was 33 years with an average of 4-year multiple sclerosis history, and 83% were women. Hepatic disorder and depression were the most frequent medical history. The most common adverse drug reactions were local pain (45.4%) and erythema (38.9%). The immediate postinjection reactions included dyspnea (10.3%), anxiety (9.7%), palpitation (8.1%), urticaria (5.4%), flushing (3.24%), chest pain (2.16%), and throat constriction (0.54%). The percentage of relapse-free patients at Month 12 was 87%, and the annual relapse rate was 0.134. An increase in the Expanded Disability Status Scale score was observed in 20% of patients, and new T2 and gadolinium-enhancing lesions were found in 34.7% and 9.4%, respectively. The rate of treatment failure was 1.6% and 4.3% according to the Modified Rio and Rio scores, respectively.

Conclusions: The 40 mg brand-generic glatiramer acetate product was well tolerated in this selected group of Iranian patients with relapsing-remitting multiple sclerosis, and patient adherence was favorable over 1 year. (. 2018; 79:XXX-XXX).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.curtheres.2018.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6008499PMC
May 2018

Epigallocatechin-3-gallate (EGCG) activates AMPK through the inhibition of glutamate dehydrogenase in muscle and pancreatic ß-cells: A potential beneficial effect in the pre-diabetic state?

Int J Biochem Cell Biol 2017 07 27;88:220-225. Epub 2017 Jan 27.

Department of Cell Physiology and Metabolism, University of Geneva Medical Center, 1 rue Michel-Servet, 1206 Geneva, Switzerland; Faculty Diabetes Center, University of Geneva Medical Center, 1 rue Michel-Servet, 1206 Geneva, Switzerland. Electronic address:

Glucose homeostasis is determined by insulin secretion from the ß-cells in pancreatic islets and by glucose uptake in skeletal muscle and other insulin target tissues. While glutamate dehydrogenase (GDH) senses mitochondrial energy supply and regulates insulin secretion, its role in the muscle has not been elucidated. Here we investigated the possible interplay between GDH and the cytosolic energy sensing enzyme 5'-AMP kinase (AMPK), in both isolated islets and myotubes from mice and humans. The green tea polyphenol epigallocatechin-3-gallate (EGCG) was used to inhibit GDH. Insulin secretion was reduced by EGCG upon glucose stimulation and blocked in response to glutamine combined with the allosteric GDH activator BCH (2-aminobicyclo-[2,2,1] heptane-2-carboxylic acid). Insulin secretion was similarly decreased in islets of mice with ß-cell-targeted deletion of GDH (ßGlud1). EGCG did not further reduce insulin secretion in the mutant islets, validating its specificity. In human islets, EGCG attenuated both basal and nutrient-stimulated insulin secretion. Glutamine/BCH-induced lowering of AMPK phosphorylation did not operate in ßGlud1 islets and was similarly prevented by EGCG in control islets, while high glucose systematically inactivated AMPK. In mouse C2C12 myotubes, like in islets, the inhibition of AMPK following GDH activation with glutamine/BCH was reversed by EGCG. Stimulation of GDH in primary human myotubes caused lowering of insulin-induced 2-deoxy-glucose uptake, partially counteracted by EGCG. Thus, mitochondrial energy provision through anaplerotic input via GDH influences the activity of the cytosolic energy sensor AMPK. EGCG may be useful in obesity by resensitizing insulin-resistant muscle while blunting hypersecretion of insulin in hypermetabolic states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biocel.2017.01.012DOI Listing
July 2017

Delineation of glutamate pathways and secretory responses in pancreatic islets with β-cell-specific abrogation of the glutamate dehydrogenase.

Mol Biol Cell 2012 Oct 8;23(19):3851-62. Epub 2012 Aug 8.

Department of Cell Physiology and Metabolism, University of Geneva Medical Center, Geneva, Switzerland.

In pancreatic β-cells, glutamate dehydrogenase (GDH) modulates insulin secretion, although its function regarding specific secretagogues is unclear. This study investigated the role of GDH using a β-cell-specific GDH knockout mouse model, called βGlud1(-/-). The absence of GDH in islets isolated from βGlud1(-/-) mice resulted in abrogation of insulin release evoked by glutamine combined with 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid or l-leucine. Reintroduction of GDH in βGlud1(-/-) islets fully restored the secretory response. Regarding glucose stimulation, insulin secretion in islets isolated from βGlud1(-/-) mice exhibited half of the response measured in control islets. The amplifying pathway, tested at stimulatory glucose concentrations in the presence of KCl and diazoxide, was markedly inhibited in βGlud1(-/-) islets. On glucose stimulation, net synthesis of glutamate from α-ketoglutarate was impaired in GDH-deficient islets. Accordingly, glucose-induced elevation of glutamate levels observed in control islets was absent in βGlud1(-/-) islets. Parallel biochemical pathways, namely alanine and aspartate aminotransferases, could not compensate for the lack of GDH. However, the secretory response to glucose was fully restored by the provision of cellular glutamate when βGlud1(-/-) islets were exposed to dimethyl glutamate. This shows that permissive levels of glutamate are required for the full development of glucose-stimulated insulin secretion and that GDH plays an indispensable role in this process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1091/mbc.E11-08-0676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3459861PMC
October 2012

Alkaloid and flavonoid rich fractions of fenugreek seeds (Trigonella foenum-graecum L.) with antinociceptive and anti-inflammatory effects.

Food Chem Toxicol 2012 Jul 20;50(7):2503-7. Epub 2012 Apr 20.

Pharmaceutics Research Center, Department of Toxicology & Pharmacology, School of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran.

The seeds of fenugreek (Trigonella foenum-graecum L.) have medicinal uses as hypoglycemic, antinociceptive and anti-inflammatory agents. We aimed to evaluate the antinociceptive and anti-inflammatory effects of the major fractions of fenugreek seeds. The methanolic extract of the plant seeds was partitioned using a liquid-liquid extraction procedure to give six major fractions. Following phytochemical screening of isolated fractions, the total extract and each fraction were evaluated for their antinociception and anti-inflammatory effects using formalin and carrageenan-induced paw edema tests respectively. The methanolic extract exhibited both antinociceptive and anti-inflammatory effects at a dose of 100mg/kg. Among the tested fractions, alkaline chloroform fraction (AKC), which was alkaloid positive in screening tests, showed the most anti-nociceptive effect in a dose-dependent manner. AKC fraction was as effective as morphine (5mg/kg) in this regard. Both aqueous and acidified chloroform fractions (ACC) could significantly inhibit paw edema at a different dose. The latter fraction dose-dependently inhibited carrageenan-induced paw edema. The results of phytochemical screening tests confirmed the presence of flavonoids in both ACC and aqueous fractions. It can be concluded that the alkaloid and flavonoid content of fenugreek seeds can be responsible for antinociception and anti-inflammatory effects of the plant respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.fct.2012.04.020DOI Listing
July 2012

Immunomodulatory activity of aqueous extract of Achillea wilhelmsii C. Koch in mice.

Indian J Exp Biol 2009 Aug;47(8):668-71

Department of Pharmacognosy, Research Center of Pharmaceutics, School of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran.

Immunomodulatory activity of aqueous extract of Achillea wilhelmsii (25, 50 and 100 mg/kg body weight for 5 days) was evaluated on body weight, relative organ weight, delayed type of hypersensitivity (DTH) response and haemagglutination titre (HT) in female Swiss albino mice. No significant body weight gain differences were recorded in various groups of animals. Significant increase in relative organ weight of spleen at 100 mg/kg was observed. No elevation in the levels of liver function test (LFT) enzymes and kidney relative weight was observed in tested doses of the plant. The extract of A. wilhelmsii elicited a significant increase in the DTH response at the dose of 100 mg/kg. In the HT test, plant extract showed stimulatory effect in all doses, however this changes were significant at 50 mg/kg. No mortality was occurred in tested doses. Overall, A. wilhelmsii showed a stimulatory effect on both humoral and cellular immune functions in mice.
View Article and Find Full Text PDF

Download full-text PDF

Source
August 2009

Comparative effects of calcium channel blockers, autonomic nervous system blockers, and free radical scavengers on diazinon-induced hyposecretion of insulin from isolated islets of Langerhans in rats.

Arh Hig Rada Toksikol 2009 Jun;60(2):157-64

Pharmaceutical Sciences Branch, Islamic Azad University, Tehran.

Hyperglycaemia has been observed with exposure to organophosphate insecticides. This study was designed to compare the effects of calcium channel blockers, alpha-adrenergic, beta-adrenergic, and muscarinic receptor blockers, and of free radical scavengers on insulin secretion from diazinon-treated islets of Langerhans isolated from the pancreas of rats using standard collagenase digestion, separation by centrifugation, and hand-picking technique. The islets were then cultured in an incubator at 37 degrees C and 5 % CO2. In each experimental set 1 mL of 8 mmol L(-1) glucose plus 125 microg mL(-1) or 625 microg mL(-1) of diazinon were added, except for the control group, which received 8 mmol L(-1) glucose alone. The cultures were then treated with one of the following: 30 micromol L(-1) atropine, 100 micromol L(-1) ACh + 10 micromol L(-1) neostigmine, 0.1 micromol L(-1) propranolol, 2 micromol L(-1) nifedipine, 50 micromol L(-1) phenoxybenzamine, or 10 micromol L(-1) alphatocopherol. In all experiments, diazinon significantly reduced glucose-stimulated insulin secretion at both doses, showing no dose dependency, as the average inhibition for the lower dose was 62.20 % and for the higher dose 64.38 %. Acetylcholine and alpha-tocopherol restored, whereas atropine potentiated diazinon-induced hyposecretion of insulin. Alpha-, beta- and calcium channel blockers did not change diazinon-induced effects. These findings suggest that diazinon affects insulin secretion mainly by disturbing the balance between free radicals and antioxidants in the islets of Langerhans and by inducing toxic stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2478/10004-1254-60-2009-1917DOI Listing
June 2009

Teucrium polium complex with molybdate enhance cultured islets secretory function.

Biol Trace Elem Res 2010 Feb 17;133(2):236-41. Epub 2009 Jun 17.

Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran, Iran.

Islet transplantation has become a promising treatment in the therapy of type 1 diabetes. Its function improvement, after isolation and before transplantation, is crucial because of their loss both in number and function of islets after isolation procedures. Trace elements sodium orthovanadate (SOV) and sodium molybdate (SM), as well as medicinal plant Teucrium polium L. (TP), showed and possessed high beneficial antioxidative potential and even hypoglycemic properties via their effect on islets. We evaluated the effect of these components in combination on cultured islet function in order to improve pancreatic islet transplantation. Rat pancreatic islets were cultured for 24 h then incubated with different concentrations of TP (0.01 and 0.1 mg/mL) alone and in combination with SOV (1 mM) or SM (1 mM). Insulin concentration in buffer media was measured as islet secretory function. Administration of TP (0.01 mg/mL), SM, and SOV alone or in combination with each other significantly increased insulin secretion at high glucose concentration (16.7 mM); insulin secretion was significantly greater in the group containing both TP and SM than other treated groups (p < 0.05). The combination of the mentioned trace elements especially molybdate with TP could improve islet cells function before transplantation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12011-009-8424-8DOI Listing
February 2010

Deletion of glutamate dehydrogenase in beta-cells abolishes part of the insulin secretory response not required for glucose homeostasis.

J Biol Chem 2009 Jan 17;284(2):921-9. Epub 2008 Nov 17.

Department of Cell Physiology and Metabolism, Geneva, Switzerland.

Insulin exocytosis is regulated in pancreatic ss-cells by a cascade of intracellular signals translating glucose levels into corresponding secretory responses. The mitochondrial enzyme glutamate dehydrogenase (GDH) is regarded as a major player in this process, although its abrogation has not been tested yet in animal models. Here, we generated transgenic mice, named betaGlud1(-/-), with ss-cell-specific GDH deletion. Our results show that GDH plays an essential role in the full development of the insulin secretory response. In situ pancreatic perfusion revealed that glucose-stimulated insulin secretion was reduced by 37% in betaGlud1(-/-). Furthermore, isolated islets with either constitutive or acute adenovirus-mediated knock-out of GDH showed a 49 and 38% reduction in glucose-induced insulin release, respectively. Adenovirus-mediated re-expression of GDH in betaGlud1(-/-) islets fully restored glucose-induced insulin release. Thus, GDH appears to account for about 40% of glucose-stimulated insulin secretion and to lack redundant mechanisms. In betaGlud1(-/-) mice, the reduced secretory capacity resulted in lower plasma insulin levels in response to both feeding and glucose load, while body weight gain was preserved. The results demonstrate that GDH is essential for the full development of the secretory response in beta-cells. However, maximal secretory capacity is not required for maintenance of glucose homeostasis in normo-caloric conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M806295200DOI Listing
January 2009

Stimulatory effects of malathion on the key enzymes activities of insulin secretion in langerhans islets, glutamate dehydrogenase and glucokinase.

Toxicol Mech Methods 2006 ;16(4):161-7

Department of Toxicology & Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Centre, Tehran University of Medical Sciences, Tehran, Iran.

Previous studies showed that malathion induces hyperglycemia mainly through influence on glucose metabolism in liver and skeletal muscles. The main objective of the present study was to determine what will happen on pancreatic key enzymes of insulin secretion, including glucokinase (GK) and glutamate dehydrogenase (GDH), if animals would be in acute or subchronic exposure to various doses of malathion, an organophosphorous insecticide in rats. In the subchronic study, malathion was administered orally at doses of 100 to 400 ppm for 4 weeks. In the acute experiment, animals received various doses of 3 to 75 mg/kg of malathion intraperitoneally. In each experiment, islets were isolated from the pancreas of rats by a standard collagenase digestion, separation by centrifugation, and hand-picking technique. The activities of the mitochondrial GDH and the nonmitochondrial GK enzymes were determined in islets homogenates spectrophotometrically. Blood sample was taken by cardiac puncture for glucose and insulin assays. In the acute experiment, malathion (3, 15, 75 mg/kg) increased blood glucose and insulin (15 and 75 mg/kg). In the subchronic experiment, malathion (100, 200, 400 ppm) increased blood glucose and insulin (200 and 400 ppm). All doses in both acute and subchronic experiments increased the mitochondrial GDH activity. Acute (15 and 75 ppm) and subchronic (200 and 400 ppm) increased the islets GK activity. It was concluded that pancreatic islet key enzymes are stimulated following acute and subchronic exposure to malathion though not enough to overcome to hyperglycemia. Activation of islets muscarinic receptors by malathion in favor of hyperinsulinemia, overproduction of glutamate/glutathione by GDH, and overproduction of glucose via increased glycogenolysis in counteracting with malathion-induced oxidative stress are possible mechanisms for observed effects. A new NOAEL acceptable daily intake must be established for malathion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15376520500191623DOI Listing
October 2012

Dopamine D2-like receptors are expressed in pancreatic beta cells and mediate inhibition of insulin secretion.

J Biol Chem 2005 Nov 29;280(44):36824-32. Epub 2005 Aug 29.

Department of Cell Physiology and Metabolism, University Medical Center, Geneva University Hospitals, CH-1211 Geneva 4, Switzerland.

Dopamine signaling is mediated by five cloned receptors, grouped into D1-like (D1 and D5) and D2-like (D2, D3 and D4) families. We identified by reverse transcription-PCR the presence of dopamine receptors from both families in INS-1E insulin-secreting cells as well as in rodent and human isolated islets. D2 receptor expression was confirmed by immunodetection revealing localization on insulin secretory granules of INS-1E and primary rodent and human beta cells. We then tested potential effects mediated by the identified receptors on beta cell function. Dopamine (10 microM) and the D2-like receptor agonist quinpirole (5 microM) inhibited glucose-stimulated insulin secretion tested in several models, i.e. INS-1E beta cells, fluorescence-activated cell-sorted primary rat beta cells, and pancreatic islets of rat, mouse, and human origin. Insulin exocytosis is controlled by metabolism coupled to cytosolic calcium changes. Measurements of glucose-induced mitochondrial hyperpolarization and ATP generation showed that dopamine and D2-like agonists did not inhibit glucose metabolism. On the other hand, dopamine decreased cell membrane depolarization as well as cytosolic calcium increases evoked by glucose stimulation in INS-1E beta cells. These results show for the first time that dopamine receptors are expressed in pancreatic beta cells. Dopamine inhibited glucose-stimulated insulin secretion, an effect that could be ascribed to D2-like receptors. Regarding the molecular mechanisms implicated in dopamine-mediated inhibition of insulin release, our results point to distal steps in metabolism-secretion coupling. Thus, the role played by dopamine in glucose homeostasis might involve dopamine receptors, expressed in pancreatic beta cells, modulating insulin release.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M505560200DOI Listing
November 2005

Synthesis and in vitro leishmanicidal activity of 2-(1-methyl-5-nitro-1H-imidazol-2-yl)-5-substituted-1,3,4-thiadiazole derivatives.

Eur J Med Chem 2005 Dec 10;40(12):1346-50. Epub 2005 Aug 10.

Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Tehran University of Medical Science, Tehran 14174, Iran.

A series of 2-(1-methyl-5-nitroimidazol-2-yl)-5-(1-piperazinyl, 1-piperidinyl and 1-morpholinyl)-1,3,4-thiadiazoles (3a-g) were synthesized and evaluated for in vitro leishmanicidal activity against Leishmania major promastigotes. The leishmanicidal data revealed that compounds 3a-g had strong and much better leishmanicidal activity than the reference drug pentostam. Compound 3c (piperazine analog) was the most active compound (IC50=0.19 microM).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmech.2005.07.002DOI Listing
December 2005

Synthesis and in vitro leishmanicidal activity of 2-(5-nitro-2-furyl) and 2-(5-nitro-2-thienyl)-5-substituted-1,3,4-thiadiazoles.

Bioorg Med Chem Lett 2005 Apr;15(8):1983-5

Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman 76351, Iran.

A series of 2-(5-nitro-2-furyl) and 2-(5-nitro-2-thienyl)-5-substituted-1,3,4-thiadiazoles (5a-d and 6a-j) were synthesized and evaluated against Leishmania major promastigotes using (3)H-thymidine incorporation. Most of the compounds showed activity better than the reference drug sodium stibogluconate (Pentostam). The most active compound was 6c (IC(50)=0.1 microM).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmcl.2005.02.073DOI Listing
April 2005

Effects of malathion subchronic exposure on rat skeletal muscle glucose metabolism.

Environ Toxicol Pharmacol 2005 Jan;19(1):191-6

Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Centre, Tehran University of Medical Sciences, Tehran, P.O. Box 14155-6451, Iran.

Regarding the widespread use of organophosphorous pesticides (OP) especially malathion in environment and reported cases of muscle disturbances in human and animal, the present work was undertaken to explore effects of malathion subchronic exposure on rat leg skeletal muscle glucose metabolism by measuring key enzymes of glycogenolysis and glycolysis. Malathion was administered through food for 4 weeks at concentrations of 100, 200, and 400ppm to rats. Activities of enzymes including glycogen phosphorylase (GP), hexokinase (HK), and phosphofructokinase-1 (PFK) were measured in skeletal muscle homogenate of exposed rats. Levels of glucose and insulin were measured in blood. Four weeks administration of malathion at doses of 200 and 400ppm increased blood glucose concentrations to 44.4 and 60.6% of control, respectively. Malathion at doses of 200 and 400ppm increased blood insulin concentration to 36.6 and 143.2% of control, respectively. Malathion at doses of 100, 200, and 400ppm increased muscle PFK activity to 40.4, 53.5, and 83.1% of control, respectively. Malathion at doses of 400ppm increased skeletal muscle GP to 91.6% of control. Skeletal muscle HK was not influenced by malathion treatment. It is concluded that malathion influences muscle glycogenolysis and glycolysis as well as secretion of insulin from pancreas which all may explain diabetic potential of malathion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.etap.2004.07.002DOI Listing
January 2005

Alteration of rat hepatic glycogen phosphorylase and phosphoenolpyruvate carboxykinase activities by Satureja khuzestanica Jamzad essential oil.

J Pharm Pharm Sci 2004 Sep 24;7(3):310-4. Epub 2004 Sep 24.

Laboratory of Toxicology, Pharmaceutical Sciences Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Iran.

Purpose: Regarding reported antidiabetic effect of Satureja khuzestanica essential oil (SKEO) and important role of liver on body glucose metabolism by glycogenolysis and gluconeogenesis, we were interested to examine effect of SKEO treatment on rat hepatic key enzymes of glycogenolysis and gluconeogenesis in vivo.

Methods: Effective antidiabetic dose of SKEO (1000 ppm) was administered to rats through drinking water for 2 weeks. After 18 hours fasting post treatment under general anesthesia, the liver was removed by transverse abdominal incision and perfused with cold 0.9% saline and kept frozen at -70 degrees C until homogenized. The activities of the key enzymes glycogen phosphorylase (GP) and phosphoenolpyruvate carboxykinase (PEPKC) were analyzed in the homogenate. Blood sample was taken by cardiac puncture for glucose assay.

Results: SKEO treatment did not affect blood glucose concentrations but decreased hepatic PEPCK activity by 26% (P<0.01) of control and increased hepatic GP by 24% (P<0.01) of control.

Conclusion: Disturbance of hepatic glucose metabolism is proposed as a mechanism of antidiabetic action of SKEO which could be in relation with antioxidant property of this plant.
View Article and Find Full Text PDF

Download full-text PDF

Source
September 2004

Hyperglycemia associated with increased hepatic glycogen phosphorylase and phosphoenolpyruvate carboxykinase in rats following subchronic exposure to malathion.

Comp Biochem Physiol C Toxicol Pharmacol 2004 Apr;137(4):343-7

Department of Toxicology and Pharmacology, Laboratory of Toxicology, Faculty of Pharmacy, Pharmaceutical Sciences Research Centre, Enghelab Avenue, Tehran University of Medical Sciences, Tehran 14155-6451, Iran.

We examined the effects of subchronic exposure to malathion, an organophosphorous (OP) insecticide, on plasma glucose and hepatic enzymes of glycogenolysis and gluconeogenesis in rats in vivo. Malathion was administered orally at doses of 100, 200 and 400 ppm for 4 weeks. At the end of the specified treatment (18 h fasting after the last dose of malathion), the liver was removed. The activities of glycogen phosphorylase (GP) and phosphoenolpyruvate carboxykinase (PEPCK) were analyzed in the homogenate. Four weeks administration of malathion at doses of 100 ppm, 200 ppm, and 400 ppm increased plasma glucose concentrations by 25% (P < 0.01), 17% (P < 0.01), and 14% (P < 0.01) of control, respectively. Malathion also increased hepatic PEPCK activity by 25% (100 ppm, P < 0.01), 16% (200 ppm, P < 0.01), and 21% (400 ppm, P < 0.01) of control, respectively. In addition, malathion increased hepatic GP by 22% (100 ppm, P < 0.01), 41% (200 ppm, P < 0.01), and 32% (400 ppm, P < 0.01) of controls. We conclude that exposure of rats to malathion as a widely used OP in subchronic exposure, which resembles human exposure, may induce diabetes associated with stimulation of hepatic gluconeogenesis and glycogenolysis in favor of glucose release into the blood. The possible mechanisms including increased energy production to detoxification, depressed paraoxonase activity, and increased production of cyclic nucleotides are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cca.2004.03.009DOI Listing
April 2004

Oxidative stress and cholinesterase inhibition in saliva and plasma of rats following subchronic exposure to malathion.

Comp Biochem Physiol C Toxicol Pharmacol 2004 Jan;137(1):29-34

Department of Toxicology and Pharmacology, Faculty of Pharmacy and Laboratory of Toxicology, Pharmaceutical Sciences Research Centre, Tehran University of Medical Sciences, Tehran 14155-6451, Iran.

The aim of this study was to examine whether malathion, a commonly used organophosphate (OP), might induce oxidative stress and cholinesterase (ChE) depression in saliva and plasma in rats following subchronic exposure mimicking human exposure. Malathion was administered orally at doses of 100, 500 and 1500 ppm for 4 weeks. Oxidative stress was determined by measuring the malondialdehyde concentration, the end product of lipid peroxidation, and assessing total antioxidant power. Four weeks oral administration of malathion at doses of 100 ppm, 500 ppm and 1500 ppm depressed plasma ChE activity to 45% (P<0.01), 48% (P<0.01) and 41% (P<0.01) of control, respectively. Malathion at doses of 100 ppm, 500 ppm and 1500 ppm depressed saliva ChE activity to 73% (P<0.01), 75% (P<0.01) and 78% (P<0.01) of control, respectively. Malathion at doses of 100 ppm, 500 ppm and 1500 ppm increased plasma antioxidant power by 33% (P<0.01), 59% (P<0.01) and 118% (P<0.01) of control, respectively. Malathion did not change saliva antioxidant power. Malathion at doses of 100 ppm, 500 ppm and 1500 ppm increased plasma thiobarbituric acid reactive substances (TBARS) by 61% (P<0.01), 69% (P<0.01) and 63% (P<0.01) of control, respectively. Malathion at doses of 500 ppm and 1500 ppm increased saliva TBARS by 19% (P<0.01) and 22% (P<0.01) of control, respectively. Malathion (100 ppm) did not change saliva TBARS level. We concluded that in OP subchronic exposure, depression of ChE is accompanied by induction of oxidative stress that might be beneficial in monitoring OP toxicity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cca.2003.11.002DOI Listing
January 2004