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PubMed1992

[Examination of the effect of chlorfenvinphos on the activity of aminotransferase in plasma and liver in vitro].

In vitro experiments the effect of chlorfenvinphos on aminotransferases activities in rat plasma and liver homogenate cytoplasmic fraction was studied. As amino groups donors in the transamination reactions with plasma enzymes the next eight amino acids were used: alanine, aspartic acid, cysteine, phenylalanine, leucine, lysine, valine and asparagine, and with the liver cytoplasmatic enzymes--the same above mentioned without asparagine. In all these reactions as an amino groups acceptor alfa-ketoglutaric acid was used. To the incubation mixtures were added: 1 cm3 of the plasma or liver homogenate cytoplasmic fraction; 0.05 cm3 of chlorfenvinphos solution in ethyl acetate (0.17 mg/cm3) or 0.05 cm3 ethyl acetate. Aminotransferase activity was expressed as the amount of glutamate developing during 1 h incubation. Glutamic acid was determined spectrophotometrically after chromatographic separation on filter paper. Both in rat plasma and in liver cytoplasmic fraction all used amino acids as amino groups donors in the transamination reactions were shown. In the reactions with the blood plasma enzymes the most active donors were: alanine, aspartic acid and cysteine and with the participation of liver transaminases: alanine, aspartic acid and phenylalanine. As well in plasma, as in liver the greater activity of AlAT than of AspAT was observed. In the reaction with alanine and aspartate there was formed in the case of plasma 1.51 mumol Glu/cm3 and 1.00 mumol Glu/cm3 respectively and in the case of liver -69.07 mumol Glu/g and 53.26 mumol Glu/g respectively. Results of statistical analysis revealed that small plasma and liver aminotransferases inhibition was caused by the solvent, while the insecticide under test had no influence on the efficiency of transamination.

Animals↗
PubMed1991

[Studies on the combined effect of pesticide mixtures belonging to different chemical groups on calcium absorption in rat intestine. Part II. Chlorfenvinphos and cypermethrin].

In male Wistar rats study was made of the effect of multiple treatment (14 days) with single pesticides (chlorfenvinphos and cypermethrin) and with their mixture on intestinal calcium absorption. Pesticides were administered intragastrically through a stomach tube in a daily dose corresponding to 5% of LD50; in the case of the pesticide mixture, 5% of LD50 of each component were administered. Calcium uptake (active and passive) by duodenal sections were determined by the method of Papworth and Patrick, modified by the present authors. It was found that under the applied experimental conditions chlorfenvinphos influences the active transport of calcium, causing an increase in the values of the constants Jm (maximal transport rate) and Kt (affinity of calcium to carrier), whereas it inhibits the passive transport. Similar changes were displayed by rats exposed to cypermethrin. On the other hand, combined administration of both pesticides led to a lack of changes in the efficiency of active transport and to impairment of passive transport, as compared with control.

Animals↗
PubMed1993

[Investigation of chlorfenvinphos influence on levels of free tryptophan in blood plasma of the rat].

The authors studied the effect of chlorfenvinphos on the free tryptophan level in the plasma of blood of male Wistar rats. The animals were intoxicated with pesticide in a single oral dose of 2.6 mg/kg (0.2 LD50). The tryptophan was assayed spectrophotometrically after 2, 4, 24 and 72 hours following administration of the insecticide. The obtained results indicate that after intoxication with chlorfenvinphos there are no changes in the free tryptophan level after 2, 4 and 24 hours. After 72 hours a significant increase of this amino acid level was observed. Inhibition of the tryptophan elimination by kidney or disturbance of dynamic equilibrium in the distribution between plasma and erythrocytes, probably is the cause of this change in concentration.

Animals↗
PubMed1997

Release of interleukin-1 beta from peripheral blood monocytes and its concentration in the blood serum of the workers employed at the production of chlorfenvinphos.

Our earlier investigations of people exposed to chlorfenvinphos revealed obstructive impairment of pulmonary function and changes in collagen metabolism. In order to evaluate the role of interleukin-1 beta in the development of these changes the serum interleukin-1 beta concentration and the ability of spontaneous and LPS stimulated production of interleukin-1 beta by monocytes were determined in 25 males aged 33-54 years and employed at the department producing chlorfenvinphos (its air concentration did not exceed permissible levels). Higher spontaneous production of interleukin-1 beta was found; the remaining parameters did not differ significantly as compared to the control group of 23 healthy males.

Adult↗
PubMed1984

Dietary protein deficiency and the influence of chlorfenvinphos on the biological parameters in rats.

Male and female rats of Wistar strain were fed from the 6th week of life on during 10 and 30 days the diet containing 4.5% or 26% protein without or with addition of chlorfenvinphos (Chl) in concentrations of 5, 100 and 1000 ppm. The following was stated: In the case of optimal-protein diet (26% protein): the inhibitory effect of Chl on the body weight gain at its highest concentration; the increased relative weight of liver, ovaries and adrenals dependent on the amount of the insecticide in the diet. In the case of low-protein diet (4.5% protein): the reduced rate of the body weight gain already at 5 ppm, pronounced at 100 ppm and strongly marked at 1000 ppm of Chl; increase of the relative weight of testicles, adrenals and decrease of the relative weight of the spleen connected with the increasing concentrations of Chl. In rats with the most decreased rate of the body weight gain (in case of Chl) an increase of the relative weight of the brain. Congestion of the heart, spleen and kidneys after 30 days on diets containing 100 and 1000 ppm of Chl, independent of the amount of protein in the diet. Eosinophilic infiltrations in the lungs of rats obtaining the 100 ppm-contaminated low-protein diet during 30 days. Focal degenerative changes in the cells of the exocrine pancreas and proliferation of lymphatic nodules in the spleen mainly in rats receiving the 1000 ppm-contaminated optimal-protein diet for 30 days. After withdrawal of Chl from the diets changes caused by this insecticide showed reversal trends.

Animals↗
PubMed1984

Relationship between dietary protein level and enzymatic changes in acute poisoning of rats with chlorfenvinphos.

The acute oral toxicity (LD50) of chlorfenvinphos (Chl) showed no significant difference between Wistar rats (males and females) aged 42 days kept for 30 days on 4.5% or 26%-protein diet, but a twofold difference appeared after 60 days on these diets (LD50 was lower in low-protein rats) showing that a longer period of protein deficiency more increases the susceptibility of rats to the lethal action of Chl. During acute poisoning produced by intragastric administration of single convulsive dose of Chl (30 mg/kg body weight) to rats kept for 30 days on low-protein or optimal-protein diet, changes were observed in the activity of some enzymes in the serum and brain. Protein deficient diet increased the Chl-produced inhibition of acetylcholinesterase (AChE) activity in the brain; the augmented activity of aspartate aminotransferase (AspAT) and alanine aminotransferase (AlaAT) and glucosephosphate isomerase (PHI) appeared only in the serum of low-protein rats--these changes were more marked in females. Other enzymatic alterations caused by Chl were similar independently of the diets and also more evident in females; for comparison the rats received also standard Murigran diet. Activity of the brain aromatic amino acids aminotransferases (AAA) showed a decreasing trend in Chl-poisoned rats, while in the liver the activity of these enzymes rose, but chiefly in the rats receiving previously the diet with 26% of protein or standard diet. In the rats surviving the acute Chl poisoning, with the evidently seen convulsions, the activity of nearly all enzymes was normal after 14 days.

Acetylcholinesterase↗
PubMed1984

Effects of chlorfenvinphos on plasma corticosterone and aldosterone levels in rats.

Plasma corticosteroids concentrations, in rats intoxicated with chlorfenvinphos (p.o. single dose 6.15 mg/kg), were investigated. A significant increase of corticosterone was observed at 1 and 3 h and aldosterone from 1 to 6 h after treatment. Brain and blood AChE activity was diminished to about 10-30% for up to 24 h, with maximal inhibition in brain at 2 h after treatment. Maximal increase in plasma corticosteroids levels occurred within 1 h, while the brain AChE was only slightly inhibited at that time. Results suggest that changes in plasma corticosteroids are not related to the decrease of AChE activity in brain.

Acetylcholinesterase↗
PubMed1990

Pretreatment of rats with an organophosphorus insecticide, chlorfenvinphos, protects against subsequent challenge with the same compound.

A single oral pretreatment of rats with chlorfenvinphos (CVP) reduced toxicity of the same compound subsequently administered. This protection occurred 8 hr and became maximal 24 hr after the oral pretreatment at a dose of 15 mg/kg (about half of its LD50). The 24-hr pretreatment with CVP increased the LD50 of CVP threefold, but did not change the type of toxic signs and time to death caused by CVP. The CVP pretreatment did not appreciably change the toxicities of the cholinergic agonists, carbachol and oxotremorine, but significantly increased the toxicity of another organophosphate, dichlorvos. Oral treatment of rats with CVP (15 mg/kg) inhibited brain acetylcholinesterase (AChE) activity. This inhibition became maximal at 4 hr (about 20% of control) and lasted more than 24 hr after the administration. Twenty-four hours after oral administration of CVP (15 mg/kg), the second dose (CVP 30 mg/kg, po) was less effective in inhibiting cholinesterase activities of the brain, erythrocyte, and plasma compared with naive rats treated with the same dose. The difference in brain AChE activity between control and CVP pretreatment groups was greater in magnitude than that measured in erythrocytes. CVP concentration in plasma after the oral administration of CVP (30 mg/kg) was decreased by the CVP pretreatment. Area under the concentration vs time curve (AUC) in the CVP-pretreated group was about one-fourth of AUC in the control group. This decrease in the AUC was comparable to the decrease in the toxicity of CVP. Thus, the protection against subsequent CVP challenge may be due to the reduction in the inhibition of brain AChE activity caused by the decrease in plasma CVP concentration.

Acetylcholinesterase↗
PubMed1991

Metabolic induction of the hepatic cytochrome P450 system by chlorfenvinphos in rats.

Previous studies have shown that a single oral pretreatment of rats with the organophosphorus insecticide 2-chloro-1-(2,4-dichlorophenyl)vinyl diethyl phosphate (chlorfenvinphos, CVP) afforded protection against the toxicity of a subsequent challenge with the same compound within 24 hr. This protection may be due to the reduction in brain cholinesterase inhibition caused by the decrease in plasma CVP concentration. The purpose of this study was to investigate the mechanism of the decrease in plasma CVP concentration in relation to metabolic induction. CVP was preferentially metabolized by a liver microsomal fraction with an NADPH-generating system, compared with serum or kidney subcellular fractions. A single oral 24-hr pretreatment with CVP (15 mg/kg) increased the oral LD50 of its next dosage to threefold. The same treatment also increased CVP metabolism (to 178%), cytochrome P450 content (to 130%), cytochrome P450 reductase activity (to 130%), cytochrome b5 content (to 121%), and cytochrome P450-linked activities such as aminopyrine demethylase (to 140%) and aniline hydroxylase (to 127%) in the hepatic microsomal fraction. A single oral 24-hr pretreatment of phenobarbital (50 mg/kg), which is known as an inducer of cytochrome P450, increased the oral LD50 of CVP and all the related metabolic parameters listed above in an order of magnitude similar to that of CVP, although the increments induced by the phenobarbital treatment were greater than those induced by the CVP treatment. These results indicate that the increase in hepatic CVP metabolism may be due to the induction of the hepatic cytochrome P450 system caused by the single oral short-term treatment with CVP. This induction may be one of the reasons for the decrease in plasma CVP concentration which may be responsible for the reduction in toxicity of its next dosage.

Animals↗
PubMed1992

Pharmacokinetic analysis of protection by an organophosphorus insecticide, chlorfenvinphos, against the toxicity of its succeeding dosage in rats.

We have previously reported that the acute oral toxicity of chlorfenvinphos (CVP) is reduced by the oral pretreatment of rats with the same compound. In this report, the mechanism of this protection was clarified mainly through the physiologically based pharmacokinetic analysis. The CVP pretreatment (15 mg/kg, po, 24 hr before) reduced the lethality of po CVP greatly, and that of iv CVP to a lesser extent. Brain acetylcholinesterase inhibition by po and iv CVP was also decreased by the pretreatment. The magnitude of reduction of the inhibition caused by the po CVP was greater than that of the iv CVP. The ratio of CVP concentration between the brain and plasma was the same, regardless of the route of administration or the pretreatment. The pretreatment greatly reduced the plasma concentration and the area under the plasma concentration versus time curve (AUC) of the po CVP, but did not change appreciably that of the iv CVP. The unbound fraction of CVP in the blood or the liver was not changed by the pretreatment. According to physiologically based pharmacokinetic analysis, the decrease in AUC of the po CVP may be mainly caused by an increase in intrinsic clearance of the liver and a decrease in the partition coefficient of CVP between the emergent blood and the liver. The increase in the intrinsic clearance may be related to the metabolic induction observed in vitro. The pretreatment decreased the absorption rate constant of the po CVP. This change in combination with the above two factors which reduce AUC might be the reason for the decrease in the plasma concentration after the po CVP, and the protection against the CVP toxicity of the succeeding dosage.

Administration, Oral↗
PubMed1994

Different inhalation lethality between micron-sized and submicron-sized aerosols of organophosphorus insecticide, chlorfenvinphos, in rats.

This study was designed to evaluate that a difference in the route of absorption or the mode of lethality is responsible for the higher inhalation lethality of micron-sized organophosphorus insecticide, chlorfenvinphos (CVP), aerosols than the submicron-sized aerosols. Male Fischer 344 rats were exposed to the micron-sized (> 1 micron) or the submicron-sized aerosols (< 1 micron) for 4 h using the nose-only exposure system. LC50 of the micron-sized and the submicron-sized aerosols was 0.13 mg/l and 0.51 mg/l, respectively. Placing a drain cannula in the esophagus markedly increased LC50 of the micron-sized aerosols to 0.49 mg/l, but not that of the submicron-sized aerosols. There was no qualitative difference in lethal profile in cardiorespiration between 2 types of aerosols. The higher lethality of the micron-sized aerosols could be ascribed to swallowed CVP.

Absorption↗
PubMed1986

Detoxification of the organophosphorus insecticide chlorfenvinphos by rat, rabbit and human liver enzymes.

A good inverse correlation between the acute oral toxicity of chlorfenvinphos and its rate of oxidative detoxification in the liver exists for rats, mice, rabbits and dogs. Measurements of the rates of oxidative metabolism (O-de-ethylation) by in vitro liver preparations from rat, rabbit and human have been compared. When the results are expressed in terms of cytochrome P450, as opposed to microsomal protein, detoxification by the human liver enzyme(s) is almost as effective as that by rabbit enzyme(s). The rabbit is relatively resistant to the acute toxic action of the insecticide.

Animals↗
PubMed1999

[The impact of acute poisoning by chlorfenvinphos on the activity of antioxidant enzymes and concentration of malondialdehyde in rats].

The aim of this paper was examination of the influence of chlorfenvinphos on the activity of an antioxidant enzymes in the blood and concentration of the serum malonondialdehyd in rats. It were found increase of the activity of SOD in 24 h and decrease in the 48 h; increase CAT activity, decrease GR activity in the 48 h and increase of G-6-P-DH activity in the 24 and 48 h after intoxication. Activity of GPX did not change statistically significant. It was observed decrease of MDA concentration in the serum in 1 and 24 h after intoxication and return to value in the control groups in the 48 h. It can be concluded that the changes of the activity of enzymes and concentration of MDA in the blood indicates hypoxia in the first period of intoxication (to 24 h) and reoxidation process in the later period.

Acute Disease↗
PubMed1990

[Evaluation of the status of nasal mucosa in workers engaged in the production of chlorfenvinphos (enolophos)].

In 41 men aged from 23 to 59 years (on an average--37.5 years) and employment duration from 1-10 years (on an average--4.9 years) working in the division of chlorfenvinphos synthesis and manufacturing "enolophos"--a preparation for agriculture, laryngological examinations were carried out including cytologic assessment of nasal mucosa and olfactometric tests. Rhinoscopy as well as cytological examinations confirmed the higher prevalence of nasal mucosa changes of inflammatory or allergic character as compared to the control group. The association between duration of employment and the changes perceived was found. Simultaneously olfactometric tests revealed in this group of workers frequent lowering of odours sensation and identification threshold.

Adult↗
PubMed1993

[Evaluation of the functional observational battery of tests used for neurotoxicity detection based on the effects of exposure to chlorfenvinphos].

Functional observational battery suggested by EPA, was applied to neurotoxicity screening studies. In previous experiments an organophosphorous pesticide, chlorfenvinphos (CVP), was used. It was administered intraperitoneally to male rats at the doses of 1, 3, 6 mg/kg of body weight; edible oil was administered to the control group. Tests were performed 3 hrs, 24 hrs and 7 days after the administration of the these substances. The set of tests concerned motor, sensory and vegetative functions. The influence of the dose of 6 mg/kg on rats was particularly evident. A number of disorders, like tremor, hypersalivation, dysbasia and hypotaxia, not observed in animals to which lower doses of CVP had been administered, were noticed. The mortality rate in this group was 25%. Earlier studies revealed neurotoxicity of CVP administered at the dose of 3 mg/kg, which when compared to the present results of the experiment indicates low sensitivity of this battery of tests taken as a whole. The disadvantage of the battery lies also in applying the quality evaluation scale in many cases, which makes carrying out statistical analysis difficult. Behaviours not formulated in this scale were observed. The observation of animal locomotor activity proved to be the most reliable and objective neurotoxicity evaluation index both in the previous and present studies.

Animals↗
PubMed1997

Biochemical evaluation of the liver function in workers employed at the production of chlorfenvinphos.

In order to assess the liver damage caused by chlorfenvinphos, all the workers employed at the production of this compound were examined twice, 9 years apart. Serum concentration of bilirubin, protein components and the activity of some selected enzymes--red blood cell acetylcholinesterase (AChE), serum alkaline phosphatase (AP), gamma-glutamyltranspeptydase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and malic dehydrogenase (MDH) were determined in 41 males on the first examination. On the second examination serum bilirubin concentration and the activity of AChE, ChE, AP and ALT were determined in 35 males. As compared to the results obtained in control groups the first study showed that a lower concentration of serum proteins was accompanied by decreased globulin alpha 1 and beta percentage along with an increased globulin gamma percentage; bilirubin concentration and the activity of ALT, AST, and MDH were higher, whereas the activity of AP, GGT and AChE was lower. The results of the second study were similar--lowered activity of ChE and AP, and increased ALT activity. The results of the investigation provide support for a very slight impairment of the liver parenchyma.

Acetylcholinesterase↗
PubMed1997

[Glycolytic processes in rat liver during chlorfenvinphos intoxications].

The aim of the study was to evaluate the activity of lactate dehydrogenase (LDH) and the concentration of lactate, pyruvate and glucose in cytosolic fraction of the rat liver in chlorfenvinphos intoxication. We found the increased activity of lactate dehydrogenase, decreased concentration of pyruvate with concurrent increase in the concentration of lactate and glucose in animal groups examined. The changes in the parameters investigated indicated the enhanced glycolytic process in the liver.

Animals↗