The ultrastructure of livers of rats fed DDT and dieldrin

Liver histopathology of Baltic grey seals (Halichoerus grypus) over three decades

The liver plays an important role in the metabolism and elimination of endogenic and exogenic lipid-soluble compounds. Multiple studies have shown that polychlorinated biphenyls (PCB) and dichlorodiphenyl trichloroethane (DDT) lead to morphological changes in liver cells. The aim of the present study was therefore to analyse liver changes over time in Baltic grey seals (Halichoerus grypus) and to correlate these with historical PCB and DDT contaminations. A total of 191 liver samples were collected between 1981 and 2015 in the Gulf of Bothnia and northern Baltic Proper. Six histological features were evaluated, including portal mononuclear cell infiltration, random mononuclear cell infiltration, lipid granulomas, hepatocellular fat vacuoles, hepatic stellate cells and mild multifocal bile duct hyperplasia accompanied by portal fibrosis. Three of the six lesions showed a significant correlation with age. Furthermore, a positive correlation between portal mononuclear cell infiltration and mild multifocal bile duct hyperplasia was found. Additionally, lipid granulomas were significantly correlated with hepatic stellate cells. More importantly, hepatic stellate cells and mild multifocal bile duct hyperplasia were correlated with adipose tissue (blubber) concentrations of ƩPCB, measured in a subsample (n = 34) of all individuals. No correlation with lesions and ƩDDT concentrations were found. These results show that age is an important factor for the development of these liver lesions, but PCBs burden may be an influencing factor. This is in agreement with previous studies of marine mammals in the Baltic Sea as well as in the Arctic. We therefore conclude that not only age of the animals, but also exposure to PCBs should be taken into account when understanding and evaluating the current health status of Baltic grey seals.

Organochlorine pesticide levels and risk of Alzheimer’s disease in north Indian population

Alzheimer’s disease (AD) could result from a multifactorial process involving both genetic predisposition and exposure to environmental factors like pesticides. A case control study of 70 patients of AD and 75 controls was done to examine the association between organochlorine pesticides (OCPs) and risk of AD. OCPs (hexachlorocyclohexane (HCH), aldrin, dieldrin, endosulfan, pp′-dichlorodiphenyldichloroethylene ( pp′-DDE), op′-DDE, pp′-dichlorodiphenyltrichloroethane ( pp′-DDT), op′-DDT, pp′-dichlorodiphenyldichloroethane ( pp′ -DDD) and op′-DDD) were extracted from blood and quantitatively estimated using gas chromatography. A Mann–Whitney U test revealed significant difference in β-HCH levels ( U = 1237.00, W = 4087.00, z = −6.296, p = 0.000, r = −0.71), dieldrin levels ( U = 1449.00, W = 4299.00, z = −5.809, p = 0.000, r = −0.68) and pp′-DDE levels ( U = 2062.00, W = 4912.00, z = −2.698, p = 0.007, r = −0.59) between AD patients and controls. In conclusion, this study supports epidemiological studies that associate exposure to pesticides with increased risk of AD, and we identified the specific pesticides β-HCH, dieldrin and pp′-DDE that are associated with the risk of AD in the north Indian population. However, further research is needed to establish the potential role of these OCPs as an etiologic agent for AD case.

Endosulfan-induced hepatotoxicity is route of exposure independent in rats

Endosulfan is an important hepatotoxic agent that generates free oxygen radicals in liver. With the widespread use of endosulfan in agriculture, human beings are most likely to be exposed to it by eating food contaminated with endosulfan, exposure to its low levels by skin contact with contaminated soil, smoking cigarettes made from tobacco that has endosulfan residues on it, or by nose and whole body inhalation exposure in the farms during its application. Since endosulfan is a frequently used pesticide, and the incidence of toxic injury to the liver tissue in relation to its widespread use reported in the literature, we considered it necessary to investigate whether endosulfan-induced liver injury could be route of exposure dependent. Eighteen mature male albino Wistar rats, weighing between 180 and 220 g, were used in this study. The hepatotoxic effects of oral administration of endosulfan (5 mg/kg body weight) daily for 30 days, and 30 days whole body inhalation exposure to ungraded concentration of endosulfan were investigated in rats using serum liver enzymes and histopathological assay. At the end of the experimental period, serum alanine aminotransferase, aspartate amino transferase, alkaline phosphatase, and creatine kinase activities obtained for the group of rats exposed orally to endosulfan were not significantly different (p ≥ 0.05) from the activities obtained for rats exposed by whole body inhalation. However, the activity of these enzymes obtained for the rats exposed to endosulfan by both oral and inhalation routes were significantly increased (p ≤ 0.05) compared, respectively, to the control. Also, on microscopic examination, the liver tissues of experimental groups exhibited severe damage histopathologically. The results of the enzyme and histological analyses showed that both oral and whole body inhalation exposure to endosulfan may cause liver tissue damage in rats. The exposure to endosulfan in rats caused liver tissue damage independent of the route of exposure.

Greenland sledge dogs (Canis familiaris) develop liver lesions when exposed to a chronic and dietary low dose of an environmental organohalogen cocktail

We assessed the relationship between exposure to organohalogen polluted minke whale (Balaenoptera acutorostrata) blubber and liver morphology and function in a generational controlled study of 28 Greenland sledge dogs (Canis familiaris). The prevalence of portal fibrosis, mild bile duct hyperplasia, and vascular leukocyte infiltrations was significantly higher in the exposed group (all Chi-square: p<0.05). In case of granulomas, the frequency was significantly highest in the bitches (P generation) while the prevalence of portal fibrosis was highest in the F generation (pups) (both Chi-square: p<0.05). No significant difference between exposed and controls was found for bile acid, ALAT, and ALKP, while ASAT and LDH were significantly highest in the control group (both ANOVA: p<0.05). We therefore suggest that a daily intake of 50-200g environmentally organohalogen polluted minke whale blubber can cause liver lesions in Greenland sledge dogs. It is reasonable to infer that other apex predators such as polar bears (Ursus maritimus) and humans may suffer from similar impacts.

Dieldrin elicits a widespread DNA repair and antioxidative response in mouse brain

Dieldrin is an organochlorine pesticide that is toxic for monoaminergic neurons. This study was designed to test the hypothesis that a weak DNA repair response to dieldrin by nigrostriatal dopaminergic (DA) neurons results in depletion of striatal DA. The activity of the mammalian base excision repair enzyme oxyguanosine glycosylase was utilized as the index of DNA repair. Other measures of oxidative stress were also studied, including the regional distribution of lipid peroxidation and superoxide dismutase (SOD) activity. The effects of acute and slow infusion of dieldrin on striatal DA levels were biphasic with a transient initial depression followed by increases beyond normal steady-:state levels. Dieldrin administration caused a global oxidative stress evidenced by increased levels of lipid peroxidation in all brain regions, an effect consistent with its capacity to affect mitochondrial bioenergetics. Dieldrin also elicited strong antioxidative and DNA repair responses across the entire mouse brain. Although mitochondrial SOD was not as increased in midbrain as it was in other regions following a cumulative dose of 24 mg/kg, this response, along with the robust DNA repair response, appeared to be sufficient to protect potentially vulnerable DA neurons from cytotoxicity. However, the long-:term consequences of chronic low-:dose dieldrin exposure remain to be studied, especially in light of the concept of "slow excitotoxicity,'' which postulates that even a mild bioenergetic compromise can over time result in the demise of neurons.

Do organohalogen contaminants contribute to histopathology in liver from East Greenland polar bears (Ursus maritimus)?

In East Greenland polar bears (Ursus maritimus), anthropogenic organohalogen compounds (OHCs) (e.g., polychlorinated biphenyls, dichlorodiphenyltrichloroethane, and polybrominated diphenyl ethers) contributed to renal lesions and are believed to reduce bone mineral density. Because OHCs are also hepatotoxic, we investigated liver histology of 32 subadult, 24 adult female, and 23 adult male East Greenland polar bears sampled during 1999-2002. Light microscopic changes consisted of nuclear displacement from the normal central cytoplasmic location in parenchymal cells, mononuclear cell infiltrations (mainly portally and as lipid granulomas), mild bile duct proliferation accompanied by fibrosis, and fat accumulation in hepatocytes and pluripotent Ito cells. Lipid accumulation in Ito cells and bile duct hyperplasia accompanied by portal fibrosis were correlated to age, whereas no changes were associated with either sex or season (summer vs. winter). For adult females, hepatocytic intracellular fat increased significantly with concentrations of the sum of hexachlorocyclohexanes, as was the case for lipid granulomas and hexachlorobenzene in adult males. Based on these relationships and the nature of the chronic inflammation, we suggest that these findings were caused by aging and long-term exposure to OHCs. Therefore, these changes may be used as biomarkers for OHC exposure in wildlife and humans. To our knowledge, this is the first time liver histology has been evaluated in relation to OHC concentrations in a mammalian wildlife species, and the information is important to future polar bear conservation strategies and health assessments of humans relying on OHC-contaminated food resources.

Neurodegenerative memory disorders: a potential role of environmental toxins

The hypothesis that neurotoxins may play a role in neurodegenerative disorders remains an elusive one, given that epidemiologic studies often provide conflicting results. Although these conflicting results may result from methodological differences within and between studies, the complexity of chemical disruption of the central nervous system cannot be ignored in attempts to evaluate this hypothesis in different neurodegenerative disorders. Spencer provides a detailed review of the complex processes involved in defining the neurotoxic potential of naturally occurring and synthetic agents. Even concepts such as exposure and dose, as often reported in studies attempting to evaluate the risk imparted by a potential compound, can be deceptive. For example, although dose reflects "that amount of chemical transferred to the exposed subject", factors such as time and concentration in the organism, the ability to access the central nervous system, and how a compound reaches the central nervous system (routes of administration) or secondarily affects other organ systems leading to central nervous system disruption are clearly important to the concept of neurotoxic risk in neurodegenerative disorders. These factors would appear to explain the observed disagreements between studies using animal or neuronal models of neurotoxicity and population-based studies in humans. The importance of these factors and how a potential neurotoxin is investigated are clearly seen in the data on AD and aluminum. In contrast, the impact of MTPT on the central nervous system is more direct and compelling. Added complexity in the study of neurotoxins in human neurodegeneration is derived from data showing that agents may have additive, potentiating, synergistic, or antagonistic effects. Therefore, data from studies evaluating EMF risks could be readily confounded by the presence or absence of heavy metals (eg, arc welding). Other factors that may conceal neurotoxic causes for a given disorder focus on additional features such as genetic predispositions, physiologic changes that occur in aging, and even nutritional status that can support or hinder the affect of a given agent on the central nervous system. Finally, many studies that investigate exposure risk do not readily incorporate the five criteria proposed by Schaumburg for establishing causation. For example, if we apply Schaumburg's first criterion, epidemiologic studies often determines the presence of an agent through history, yet they cannot readily confirm exposure based on environmental or clinical chemical analyses to fulfill this criterion for causation. Additional limitations in research design along with the populations and methods that are sued to study neurotoxins in human neurodegenerative disorders often fail to meet other criteria such as linking the severity and onset with duration and exposure level. Therefore, although studies of agents such as MTPT provide compelling models of neurotoxins and neurodegeneration in humans, disorders such as ALS, PD, and particularly AD will require additional effort if research is to determine the contribution (presence or absence) of neurotoxins to these neurologic disorders.

Cytological and biochemical effects of a mixture of 20 pollutants on isolated rainbow trout (Oncorhynchus mykiss) hepatocytes

Isolated hepatocytes of rainbow trout (Oncorhynchus mykiss) were exposed to different concentrations (1x, 10x, 50x) of a complex mixture of 20 environmentally relevant contaminants (PAHs, PCBs, pesticides) typical of the chemical burden of surface waters and sediments of small rivers in southwest Germany to investigate sublethal cytological and biochemical alterations. Results document that all concentrations clearly induced biochemical and morphological changes. The activities of enzymes such as lactate dehydrogenase and catalase as well as the rate of lipid peroxidation were significantly increased, whereas acid phosphatase activity decreased. Cytopathological effects included deformation of cellular shape, deformation and dilation of the nuclear envelope, increase in heterochromatin, nuclear inclusions, heterogeneity of mitochondria, vesiculation of RER cisternae, as well as increases in myelinated bodies, lysosomes, and peroxisomes. If compared with cytological alterations induced in isolated rainbow trout hepatocytes after exposure to sediment extracts from rivers of corresponding contamination, cytological effects of exposure to the complex chemical mixture displayed numerous similarities.

Environmental pesticide exposure as a risk factor for Alzheimer's disease: a case-control study

The aim of this study was to evaluate the influence of pesticide exposure on the development of Alzheimer's disease (AD), taking into account the potentially confounding factors (genetic, occupational exposure, and sociodemographic). The 1924 study participants (>70 years old) were randomly selected in the Saguenay-Lac Saint-Jean region (Quebec, Canada). The AD diagnosis was established in three steps according to recognized criteria. Sixty-eight cases were paired with a nondemented control for age (+/-2 years) and sex. Structured questionnaires addressed to subjects and proxy respondents allowed a description of the sociodemographic characteristics, lifestyle characteristics, and residential, occupational, familial, and medical histories. Assessment of environmental exposure to pesticides was based on residential histories and the agriculture census histories of Statistics Canada (1971-1991) for herbicide and insecticide spraying in the area. Statistical analyses were performed with a logistic regression, adjusting for potential confounding factors. The results failed to show a significant risk of AD with an exposure to herbicides, insecticides, and pesticides. However, future investigations are needed to establish more precisely the identification, measurement, mobility, and bioavailability of neurotoxic pesticide residues in relation to AD.

Monograph: reassessment of human cancer risk of aldrin/dieldrin

In 1987, the US Environmental Protection Agency (EPA) classified aldrin and dieldrin as category B2 carcinogens, i.e. probable human carcinogens, based largely on the increase in liver tumors in mice fed either organochlorine insecticide. At that date, the relevant epidemiology was deemed inadequate to influence the cancer risk assessment. More time has now elapsed since early exposures of manufacturing workers to aldrin/dieldrin; therefore, updated epidemiological data possess more power to detect exposure-related differences in cancer risk and mortality. Also, recent experimental studies provide a plausible mode of action to explain the mouse specificity of dieldrin-induced hepatocarcinogenesis and call into question the relevance of this activity to human cancer risk. This monograph places this new information within the historic and current perspectives of human cancer risk assessment, including EPA's 1996 Proposed Guidelines for Carcinogen Risk Assessment. Updated epidemiological studies of manufacturing workers in which lifetime exposures to aldrin/dieldrin have been quantified do not indicate increased mortality or cancer risk. In fact, at the middle range of exposures, there is evidence of a decrease in both mortality from all causes and cancer. Recent experimental studies indicate that dieldrin-induced hepatocarcinogenesis in mice occurs through a nongenotoxic mode of action, in which the slow oxidative metabolism of dieldrin is accompanied by an increased production of reactive oxygen species, depletion of hepatic antioxidant defenses (particularly alpha-tocopherol), and peroxidation of liver lipids. Dieldrin-induced oxidative stress or its sequelae apparently result in modulation of gene expression that favors expansion of initiated mouse, but not rat, liver cells; thus, dieldrin acts as a nongenotoxic promoter/accelerator of background liver tumorigenesis in the mouse. Within the framework of EPA's Proposed Guidelines for Carcinogen Risk Assessment, it is proposed that the most appropriate cancer risk descriptor for aldrin/dieldrin, relating to the mouse liver tumor response, is 'not likely a human carcinogen', a descriptor consistent with the example of phenobarbital cited by EPA.

Toxicity of dieldrin for dopaminergic neurons in mesencephalic cultures

Dieldrin can be retained for decades in lipid-rich tissue and has been measured in some postmortem PD brains. Dieldrin has been reported to deplete brain monoamines in several species and has been shown to inhibit mitochondrial respiration. To further investigate the possibility that it may be involved in the pathogenesis of parkinsonism, its toxicity for dopaminergic (DA) neurons was assessed in a mesencephalic cell culture model. Primary neuronal cultures of mesencephalic neurons were prepared from fetal rats or fetal mice, grown for 1 week and incubated with Dieldrin (0.01-100 microM) for 24 or 48 h. Toxicity for DA neurons was determined by measuring density of surviving tyrosine hydroxylase immunoreactive (TH-ir) cells. Toxicity for gamma-aminobutyric acid (GABA)-ergic neurons was determined by measuring survival of glutamate decarboxylase (GAD)-ir neurons. General, nonselective cytotoxicity was determined by counting cells visualized by phase contrast microscopy or by DAPI-stained cells with fluorescence microscopy. Dieldrin exposure for 24 h resulted in a dose-dependent decrease in survival of TH-IR cells (DA neurons) with a 50% decrease (EC50) produced by 12 microM in rat mesencephalic cultures. Dieldrin also produced a dose- and time-dependent decrease in mouse DA-ergic and GABA-ergic neurons in mouse mesencephalic cultures. GABA-ergic neurons were less sensitive to the toxin compared to DA-ergic neurons. Cellular uptake of 3H-DA was also affected by lower concentrations of Dieldrin (EC50 = 7.98 microM) than uptake of 3H-GABA (EC50 = 43 microM). Thus, Dieldrin appears to be a relatively selective DA-ergic neurotoxin in mesencephalic cultures. Dieldrin, which may be ubiquitous in the environment, is proposed as an agent which can initiate and promote dopaminergic neurodegeneration in susceptible individuals.

Parkinson's disease and brain levels of organochlorine pesticides

Epidemiological studies have suggested an etiologic relationship between pesticide exposure and Parkinson's disease (PD). Organochlorine pesticides were assayed in postmortem brain samples from 20 PD, 7 Alzheimer's disease (AD), and 14 nonneurological control cases. The three groups were similar in age at death, sex, and demographic variables. Only two of 16 pesticide residues screened were detected. A long-lasting residue of DDT (pp-DDE) was found in the majority of cases of PD and AD, as well as in all the control cases; pp-DDT was significantly more likely to be found in AD controls than the PD cases (Fisher's exact two-tailed, p = 0.04). Dieldrin was detected in 6 of 20 PD brains, 1 of 7 AD, and in none of 14 control samples. Despite the relatively small number of brains assayed, the association between Dieldrin and the diagnosis of PD was highly significant (p = 0.03). Dieldrin, a lipid-soluble, long-lasting mitochondrial poison, should be investigated as a potential etiological agent of Parkinsonism.

Effect of benomyl toxicity on some liver constituents of albino rats

Weanling albino rats were fed 0-600 mg/kg body weight methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate (benomyl) for 7 d, and effects on protein, glycogen, and vitamin A constituents were recorded. Doses fed in rat chow were 0, 40, 80, 125, 165, 200, 240, 280, 320, 360, 400, 440, 480, 520, 560, and 600 mg/kg body weight. There was a dose-dependent decrease in the concentration of liver constituents, of which glycogen decreased the most. Histopathological findings included cellular swelling and edema of the liver, kidney, and spleen.

How toxic is 2,3,7,8-tetrachlorodibenzodioxin to humans?

The tissue levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) measured in different species are reviewed. Based on the correlation of tissue levels and a toxic response in different species, humans are less or no more susceptible to the toxic effects of TCDD than most of the laboratory animals that have been studied. Thus, the present exposure of the general population to environmental levels of TCDD are related compounds should not be of concern.

Organochlorine insecticide problems in livestock

1. Antidotal therapy for acute OC intoxications is symptomatic and supportive. Use sedatives to control convulsions and AC to adsorb any pesticide remaining in the gut, and wash topical exposures. 2. Published kinetics should be applied to field situations with caution. In general, residues decline relatively quickly immediately following the last exposure; thereafter, the rate slows considerably. The elimination-rate constant and, hence, the half-life of any given OC is dependent on many variables that usually are not known under field conditions. This fact may result in serious errors if literature values are relied on too heavily in predicting the outcome of "natural" contamination. As a rule of thumb, elimination data derived from animals experimentally fed to plateau concentrations may be regarded as fairly conservative for such purposes, if the contaminated animals are maintained in a normal fashion. Probably the least risky method of predicting return to marketability is using frequent samples, taken at regular intervals (for example, 1 to 2 weeks) during the first month after last exposure, to adjust literature values. 3. Residues from larger dosages and shorter exposures tend to be smaller in proportion to dose and are eliminated more quickly than those resulting from longer exposures and smaller doses. 4. Activated charcoal is of universal benefit only if given immediately after exposure. 5. Pharmaceutical modifiers of xenobiotic metabolism such as phenobarbital are of very limited value. The particular type and amount of residual OC and the potential economic benefit of therapy should be considered thoroughly before undertaking such therapy. In most cases, the expense won't be justified. 6. Mineral oil increases the fecal excretion of some OC. Fecal excretion, however, is so small in relation to total body burdens that even a several-fold increase may not be useful economically except when residue concentrations are low to start with. 7. Nutritional strategies have the advantage of being very cheap. Practitioners should remember, however, that tissue concentrations actually may increase as body fat decreases. The costs of maintaining animals for an extra 6 to 10 months should be considered before undertaking such an effort.(ABSTRACT TRUNCATED AT 400 WORDS)

Light and electron microscopical changes in the liver of mice following treatment with aminotriazole

Light and electronmicroscopical alterations in the liver of mice were shown oral administration of aminotriazole. Intensity of damage depends on concentration. High dosage affects all inter- and intralobular portions. Presented light microscopical results show, next to an extreme hypertrophy of hepatocytes, well distinguishable nuclear deformations and increased pyknotic nucleoli. The cytoplasm contains numerous vacuoles and lipid droplets. Fine structural alterations after drug administration include defects on all cell organelles and membranes. Especially proliferations of smooth ER cisternae with simultaneous reductions of rough ER cisternae, increase of microbodies as well as numerous defects on mitochondria were obvious. Interpretations of the mode of action of aminotriazole is based on ultrastructural results and biochemical knowledge on this herbicide and compared with other toxicants.

Pollutants in harp seals (Phoca groenlandica). I. Organochlorines

Between 1976 and 1978, 248 harp seals were sampled from 5 locations in the Northwest Atlantic and Arctic for organochlorine (OC) residue analysis in tissue. Blood, kidney, brain, muscle and blubber samples were analysed for PCB, DDT, dieldrin, hexachlorobenzene (HCB), and heptachlor epoxide. Levels were generally greatest in blubber tissue. Overall, mean levels of DDT and PCB were greater than those of other OC. A barrier prevented OC compounds from accumulating in the brain to the level one might expect in lipid tissues. Positive correlations were found between 1: DDT and PCB, 2: DDT and dieldrin, and 3: PCB and deildrin. Male harp seals bioaccumulated DDT, PCB, heptachlor epoxide and dieldrin with age. As a group, adult males sampled in the Gulf of St. Lawrence carried the highest concentrations of all OC, except that chlordane did not appear to bioaccumulate and levels of hexachlorobenzene were minimal. Females generally ceased exhibiting significant bioaccumulation once breeding age was reached, due to transplacental and transmammary residue transfer of OC from mother to pup. There were some significant differences in OC levels between locations with DDT: Gulf greater than Front; PCB: Gulf greater than Front; dieldrin: Gulf greater than Front; heptachlor epoxide: Front greater than Gulf. No significant differences were found, however, when northern locations (Grise Fiord, Northwest Greenland, Pangnirtung) were compared to southern (Gulf, Front) on a group basis. The latter is not surprising in view of the harp seals extensive cyclical annual migration between the southern breeding grounds and the High Arctic.

The effects of acute carbaryl exposure on clotting factor activity in the rat

Male Sprague-Dawley rats were placed on a drinking solution containing either 10 parts per million (ppm) carbaryl or water for 30 days. Plasma was analyzed for the prothrombin time, partial thromboplastin time, fibrinogen, and clotting factor activity for coagulation factors II, V, VII, VIII, IX, X, XII and the platelet count. Only two hematological parameters measured were statistically different from the controls; these parameters were the platelet count and factor VII activity, both of which were reduced. Histological examination of the hepatic tissue illustrated that a number of pathological changes were occurring.

The effects of long-term malathion or diazinon ingestion on the activity of hepatic synthesized clotting factors

Female Sprague-Dawley rats were placed on a drinking solution of 1 ppm Diazinon or malathion dissolved in water for 6 months. At the conclusion of the experiment liver tissue and plasma were examined. Clotting studies included the prothrombin time (PT), partial thromboplastin time (APTT), fibrinogen, and factors II, V, VII, X, plus the platelet count. Hepatic morphology, basically hepatocyte degeneration, was altered by malathion while diazinon had no notable effect. Likewise, malathion prolonged both the PT and APTT, the only changes in clotting activity.

Effects of acute pesticide poisoning on blood clotting in the rat

Male Sprague-Dawley rats were treated with 1 ml of diazinon or malathion, 1750 ppm given orally by gavage. Clotting determinations included the prothrombin time, partial thromboplastin time, fibrinogen, and coagulation factors II, V, VII, and X, plus the hematocrit and platelet count. The results suggest that insecticides influence the clotting times of rats ingesting these insecticides even after as short a time span as 2 hr.

The effects of 1,1-di(p-chlorophenyl)-2-chloroethylene (DDMU) on hepatic morphology of Japanese quail

The effects of dietary administration of 1,1-di(p-chlorophenyl)-2-chloroethylene (DDMU) to Japanese quail at a concentration of 100 ppm were investigated for periods of up to 32 days. Hepatic morphology was studied by light microscopy. Histologic changes observed included cytoplasmic and nuclear degeneration in the hepatocytes followed by severe lipid accumulation and hepatocellular hypertrophy. There was a progressive increase in cytoplasmic vacuoles containing lipid up to Day 24 followed by a decrease by Day 32 when the numbers of vacuoles remained greater than those in untreated quail livers. The vacuoles showed a distribution which followed the functional acinar units of the liver. Increased numbers and hypertrophy were observed in Kupffer cells and fibrocytes. There was an occasional necrotic hepatocyte observed but this lesion was not a prominent feature. Hepatocellular hyperplasia occurred as the lipid accumulation decreased. The histologic findings are compared with the biphasic response previously described.

Studies on the effect of dietary protein and fat content upon DDT metabolism in rat liver

Rats were supplied with 25 kinds of food, which were divided into 5 classes of protein and 5 classes of fat content, to examine the effect of dietary protein and fat on the metabolism and retention of DDT in the liver. The results suggested that dietary protein and fat changed DDT and its metabolites concentration in liver. The concentration of DDT decreases according to the increase of dietary protein content. The concentration of DDT and its metabolites in liver increases when the dietary fat content increases. Polynomial and multiple regression analyses were carried out to confirm the effect of dietary protein and fat on DDT metabolism. The results suggest that the residual concentration of DDT and its metabolites (DDD and DDE) is a function of dietary protein and fat content, and can be represented in equation form. The estimation of the concentration of DDT and its metabolites from the equation agrees well with the measured concentration in liver.

Transfer of 2,4,5,2',4',5'-hexachlorobiphenyl and 2,2-bis-(p-chlorophenyl),1,1,1-trichloroethane (p,p'-DDT) from maternal to newborn and suckling rats

Pregnant rats were given a small dose of 14C-2,4,5,2',4',5'-hexachlorobiphenyl (HCB) and 3H-DDT intraperitoneally. The transfer of HCB and DDT through the placenta and milk was then investigated. Transfer through the placenta was 2.7 and 1.5% (respectively) of the initial doses; transfer through milk was 39.2 and 21.5%. HCB is obviously more transferable than DDT through the placenta and milk, the ratio of the amount of HCB transferred through milk to the amount transferred through the placenta agrees with that for DDT. Concentrations of HCB and DDT in the whole suckling rat increases rapidly and is similar to the sigmoidal growth curve and change in lipid concentration. Therefore, the concentrations of the chemicals in the maternal tissue generally decrease in comparison with those of nonpregnant rats.

Induction of mixed function oxidases on oral administration of dieldrin

The administration of dieldrin (30 mg/kg body weight) caused an increase in the liver weight of rats. The metabolism of aflatoxins B1 and G1 by the microsomes obtained from the liver of dieldrin-treated animals was enhanced significantly as compared to the controls showing that dieldrin increased the activity of mixed function hydroxylases. Dieldrin caused an increase in the activity of liver microsomal NADPH oxidase and a decrease in the lipid peroxidation. Dieldrin brought about an increase in the phosphatidylcholine content of rat liver.

Octabromobiphemyl-induced ultrastructural changes in rat liver

Single oral administration of octabromobiphenyls at 1,000 mg/kg, or two consecutive doses of 3,000 mg/kg, to rats produced liver enlargement. Light microscopic examination revealed hepatocellular hyperplasia, margination of basophillic cytoplasm, and foamy cytoplasmic alteration on the third day posttreatment. Laminated cytoplasmic inclusions developed seven days after treatment and subsequently disappeared about one week later. Under electron microscopy, the cytoplasmic margination corresponded to peripherally displaced granular reticulum and the foamy cytoplasm was recognizable as proliferating agranular reticulum with depletion of particualte glycogen. The cytoplasmic inclusions were identified as myelin configurations enclosing lipid bodies, membrane-bound vacuoles with whorled figures, and vesicular agranular reticulum. In the early developmental stages, the myelin figures were studded with ribosomes and associated with the granular reticulum.

Dieldrin toxicity and in vivo incorporation of DL-(1-14 C)leucine

The in vivo effect of a single oral dose (30mg/kg body weight) of dieldrin on proteolipid and phosphatidopeptide content of liver and brain and on total protein of liver, brain, plasma, muscle and kidney of rat was studied. Incorporation of (14C)leucine into total protein of liver was increased whereas labelling of total protein of muscle was decreased. Labelling of total protein of other tissues was unchanged. Incorporation into liver phosphatidopeptides was increased and this was consistent with an involvement of group. Proteolipid protein content of brain was increased and that of liver unchanged. There was, however, no change in the labelling of brain or liver proteolipids.

Role of cyclic adenosine 3':5'-monophosphate in the action of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (DDT)on hepatic and renal metabolism

The possibility whether alterations in the cyclic AMP-adenylate cyclase-phosphodiesterase system play a role in the action of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (DDT) on hepatic and renal carbohydrate metabolism was investigated. Administration of exogenous cyclic AMP (10mg/100g) was found to mimic the action of DDT which enhanced the activities of pyruvate carboxylase, phosphoenolpyruvate carboxylase, fructose 1,6-diphosphatase and glucose 6-phosphatase in both liver and kidney cortex, elevated the concentration of blood glucose and urea and decreased the amount of hepatic glycogen. Treatment with theophylline augmented the effects of a submaximal dose of this halogenated hydrocarbon on serum urea and glucose as well as the key gluconeogenic enzymes in liver and kidney cortex. Addition of DDT in vitro to liver and kidney homogenates resulted in a significant enhancement of adenylate cyclase activity. Hepatic and renal slices from rats already treated with DDT displayed an increased ability to convert [(3)H]adenosine into cyclic [(3)H]AMP. Whereas kidney-cortex slices excised from rats given caffeine and DDT produced an even greater amount of cyclic [(3)H]AMP, imidazole, propranolol and hydrazine prevented the insecticide-stimulated rise in cyclic nucleotide production. In contrast, prostaglandin E(1) failed to exert any significant effect on DDT-induced increases in cyclic [(3)H]AMP synthesis from radioactive adenosine. The present study and our previous findings (Kacew & Singhal, 1973e) support the concept that the DDT-induced alterations in carbohydrate metabolism of liver and kidney cortex may be related to an initial stimulation of the cyclic AMP-adenylate cyclase system in these tissues.