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At least 19 recordsLinked to original sources
PubMed1979

Action of exogenously administered steroid hormones following perinatal exposure to polybrominated biphenyls.

Polybrominated biphenyls (PBBs) have produced a variety of effects including alterations in the endocrine system and in the activity of microsomal mixed-function oxidases (MFOs). Because steroid hormones are substrates for MFOs, effects of PBBs on the endocrine system may be a consequence of enhanced steroid hormone catabolism. Therefore, as a first step in evaluating the effect of PBBs on steroid hormone catabolism. Therefore, as a first step in evaluating the effect of PBBs on steroid hormone metabolism, it was of interest to determine effects of perinatal exposure to PBBs on the response to exogenously adminstered steroid hormones. Rats were exposed to 0, 10, or 100 ppm PBBs from d 8 of gestation until d 28 postpartum, when experiments were conducted. Responses to labeled steroid hormones were generally modified in a manner directly related to PBB dose and were correlated with changes in serum and target tissue retroactivity. Stimulated metabolism of steroid hormones may account, at least in part, for endocrine-related alterations produced by PBBs. Although the potential for decreased reproductive capacity following PBBs cannot yet be accurately predicted, these experiments suggest that fertility may be reduced following PBBs as a consequence of accelerated steroid hormone metabolism and/or excretion.

Animals↗
PubMedDate not supplied

Comparative toxicity of polychlorinated biphenyl and polybrominated biphenyl in the rat liver: light and electron microscopic alterations after subacute dietary exposure.

The comparative toxicity of polychlorinated biphenyl (PCB) and polybrominated biphenyl (PBB) in livers was studied in male Holtzman rats. Four-week-old animals were fed at dietary levels of 0, 5, 50, or 500 ppm for 5 weeks and then sacrificed. The mean liver-body weight ratios of the 50 and 500 ppm groups were increased. Histopathologic examination of the livers revealed fatty degenerative change associated with both compounds. This change was more marked at 500 than at 50 ppm. Various sized lamellar cytoplasmic inclusions were detected in livers of animals fed 500 ppm of either compound. However, the inclusions were more numerous in the PBB-treated rats. Several animals fed 50 ppm PBB had a few inclusions. In rats that received 500 ppm PBB, hypertrophic degenerative hepatocytes were present around the central veins. On the periphery of this change there were occasionally multinucleated hepatocytes. Electron microscopic examination at a dose level of 5 ppm in both the PCB and PBB groups showed a slight proliferation of smooth endoplasmic reticulum (SER), a moderate increase of lipid droplets and some liposomes, and a marked proliferation of Golgi condensing vesicles containing lipoprotein particles. A decreased number of mitochondria and lysosomes was also observed. At 50 ppm, similar but more marked ultrastructural alterations were seen. In addition, an increased number of branched and cup-shaped profiles of mitochondria and a decreased number of Golgi condensing vesicles containing lipoprotein particles were observed. Concentric membranous cytoplasmic whorls were encountered only in the 50 ppm PBB-treated rats. At 500 ppm the number of mitochondria decreased in both groups. There was also a marked increase in the number of SER and liposomes concomitant with a decreased number of Golgi condensing vesicles containing lipoprotein granules. Membranous whorls were also present in the 500 ppm groups.

Animals↗
PubMed1975

Effects of polychlorinated biphenyls and terphenyls and polybrominated biphenyls on pentobarbital sleeping times of Japanese quail.

Polychlorinated biphenyls (Aroclor 1221, 1232, 1242, 1248, 1254, 1260, 1262, and 1268), polychlorinated terphenyls (Aroclor 5460), a mixture of polychlorinated biphenyls and terphenyls (Aroclor 4465) and polybrominated biphenyls (BP-6) were administered in a single dose, 100 mg/kg body weight injected orally, to mature male and female Japanese quail. Two hr after Aroclor treatment, pentobarbital sleeping times were prolonged (2 to 3 times control) in both male and female quail. Twenty-four hr after treatment, sleeping times were similar to those of controls. However, 48 hr after treatment with Aroclor 1248 through Arolcor 5460 and with BP-6, sleeping times of males were only 1/2 those of controls, whereas after treatment with Aroclor 1221, 1232 and 1242, sleeping times were similar to those of controls. The reduction in sleeping times of male quail 48 hr after administration of PCBs was correlated with the percentage of chlorine in the PCB with greater reductions in male than female quail. The response after three days ad libitum feeding of 300 ppm of each substance was the same as the response 48 hr after a single oral injection. Although very few birds died from the toxicity of the Aroclors and BP-6, mortality was greatly increased during anesthesia when the pentobarbital was administered two hr after single oral dosing.

Animals↗
PubMed1977

The biological effects of polybrominated biphenyls in avian species.

Polybrominated biphenyl (PBB), structurally similar to polychlorinated biphenyl (PCB), affects feed intake, egg production, and hatchability of fertile eggs in chickens and quail. Subcutaneous edema of the neck and shoulder are common abnormalities of hatched chicks from PBB-fed dams. No characteristic teratogenicity is evident. Offspring hatched are less viable during their first 3 weeks of life. PBB does not produce thinner egg shells or lower egg weights. The ratio of PBB egg content to dietary level is 1.3-1.5:1.0. The biological half-life of PBB in eggs is calculated to be 17 days. Tissue residues are higher in males than females because egg production is a major excretory route for PBB. Polybrominated biphenyl feeding causes tissue changes in size, structure and/or function in the liver, thyroid, testes, comb, heart, spleen, bursa of Fabricus, and blood. Liver enlargement, porphyria and microsomal enzyme induction results from PBB administration. The spleen, bursa and comb are reduced in size, whereas the thyroid increases after PBB feeding. A characteristic of PBB and PCB toxicity is hydropericardium and general edema.

Animals↗
PubMed1976

Distribution and clearance of polybrominated biphenyls in cows and calves.

The distribution and clearance of polybrominated biphenyls were determined in two cows and a calf fed polybrominated biphenyls by boluses, by placental transport to a calf from a contaminated dam, and to another calf via milk from the contaminated dam. Feces were an important route of excretion of polybrominated biphenyls during exposure and the period when the contaminated feed was cleared from the digestive tract. Approximately 50% of single intraruminal doses of these hydrocarbons were cleared by 168 h. Free polybrominated biphenyls in urine could not be quantitated. However, 24% of carbon-14 from tetrachlorobiphenyl was recovered, suggesting that significant quantities of halogenated biphenyl may be excreted in urine. Milk was also an important excretion route with one cow excreting 23% of the polybrominated biphenyl dose in 168 days. Concentrations of polybrominated biphenyls in the fat of most tissues were similar, with higher concentrations in liver and lower in the nervous system. Gross or histopathologic lesions of tissues collected at necropsy could not be related specifically to polybrominated biphenyl toxicity.

Adipose Tissue↗
PubMed1978

Absence of plant uptake and translocation of polybrominated biphenyls (PBBs).

Studies of polybrominated biphenyl (PBB) uptake by plants have been conducted in hydroponic solutions and in greenhouse experiments with soil. Autoradiograms of corn and soybean seedlings grown in hydroponic solutions showed no translocation of 14C-PBB from 14C-PBB-treated solutions to plant tops or within the leaf from 14C-PBB-treated spots on the upper leaf surface. A significant portion of the 14C-PBB associated with the roots was removed when the roots were dipped in acetone. Three root crops (radishes, carrots, and onions) were grown in two soils, each treated with a mixture of FireMaster BP-6 (PBB) and 14C-PBB to achieve final concentrations of 100 ppm and 100 ppb. All roots showed more PBB when grown in the soil with the lower clay and organic matter content than they did when grown in the soil with more clay and organic matter. In the latter soil (clay loam) no PBB was detected in any roots from the 100 ppb treatment. More PBB was associated with roots of carrot than of radish or onion. Corn leaf whorls containing dust from a PBB contamination soil and washed radishes from a heavily contaminated garden showed no PBB.

Biphenyl Compounds↗
PubMed1978

Effects of activated carbon, phenobarbital, and vitamins A, D, and E on polybrominated biphenyl excretion in cows.

Twelve cows environmentally contaminated with polybrominated biphenyl residues were in a balanced two-period changeover experiment. The treatments were activated carbon and sodium phenobarbital; sodium phenobarbital and injections of vitamins A, D, and E; activated carbon, phenobarbital, and vitamins A, D, and E; and control. A standard roughage and concentrate diet was fed. Average initial concentrations of polybrominated biphenyls in the milk fat ranged from 92 to 236 ppm. The experimental treatments did not affect significantly excretion of polybrominated biphenyls in milk and feces or the apparent half-life of residues in milk fat averaged 60 days but ranged from 36 to 301 days. The longer half-life in early lactation than in later lactation indicated an effect of change of body weight on half-life. Milk was the major route of excretion, averaging 6.5 times that of fecal excretion. Polybrominated biphenyl in milk fat, body fat, blood, and feces followed parallel concentrations troughout the study.

Adipose Tissue↗
PubMed1978

Studies on the microsomal metabolism and binding of polybrominated biphenyls (PBBs).

The metabolism of polybrominated biphenyls (PBBs) was studied in vitro by using rat liver microsomes in the presence of NADPH and atmospheric O2. Quantitative recoveries of all PBBs were obtained after incubations with control or 3-methylcholanthrene (MC) induced microsomes. Of the twelve major components, losses of only peaks 1 (2,4,5,2',5'-pentabromobiphenyl) and 3 (a hexabromobiphenyl) were observed following incubations with microsomes from phenobarbital (PB)- or PBBS- pretreated rats. Of seven structurally identified PBB components, only peak 1 has a bromine-free para position. Peaks 1, 2, and 5 all have two adjacent unsubstituted carbons, yet only peak 1 is metabolized. Of two dibromobiphenyl model compounds studied, the 2,2'-congener was very rapidly metabolized by PB-induced microsomes whereas its 4,4'-isomer was not. These results suggest that the presence of a free para position is required for the metabolism of brominated biphenyls. Of lesser importance appears to be the number of bromines or the availability of two adjacent unsubstituted carbons. In vivo evidence for the metabolism of peaks 1 and 3 was also provided by their drastically diminished levels in liver and milk extracts. When a 14C-PBB mixture consisting almost exclusively of peaks 4 (2,4,5,2',4',5'-hexabromobiphenyl) and 8 (2,3,4,5,2',4',5'-heptabromobiphenyl) was incubated with PB- or PBBs- induced microsomes and NADPH, only traces of radioactivity remained with the microsomes after extensive extraction. However, less radioactivity was bound to microsomes from MC pretreated or especially control rats. No radioactivity was bound to exogenous DNA included in similar microsomal incubations, regardless of the type of microsomes used. Under the same conditions, [3H]-benzo[a]pyrene metabolites were bound to DNA, and PBB-induced microsomes enhanced this binding more than six-fold.

Animals↗
PubMed1979

Cohort study of Michigan residents exposed to polybrominated biphenyls: epidemiologic and immunologic findings.

Polybrominated biphenyls (PBB) were dispersed widely in Michigan by a 1973 shipping accident in which PBB was introduced into cattle feed. Human exposure resulted principally from ingestion of contaminated dairy food products. To determine whether PBB exposure has or will cause acute or chronic illness, a prospective cohort study of 4545 persons has been undertaken. Three exposure groups were sought; all persons living on PBB-quarantined farms; persons who had received food directly from such farms; workers (and their families) engaged in PBB manufacture. Enrollment rates were 95.6, 95.1 and 78.0%. Also enrolled were 725 persons with low-level PBB exposure. All were queried concerning 17 symptoms and conditions related possibly to PBB. Venous blood was drawn on 3639 and analyzed for PBB by gas chromatography. Mean serum PBB levels were 26.9 ppb in quarantined farm families, 17.1 in recipients, 43.0 ppb in workers, and 3.4 ppb in the low exposure groups. No associations were found between serum PBB levels and symptom prevalence rates. To evaluate peripheral lymphocyte function, T and B cell quantitation and in vitro responses to 3 nonspecific mitogens were studied in 34 persons with highest PBB levels (mean, 787 ppb), and in 56 with low values (mean, 2.8 ppb). No statistically significant differences in lymphocyte number or function were noted.

Adolescent↗
PubMed1979

Effect of polybrominated biphenyls on the development of hepatic excretory function.

Polybrominated biphenyls (PBBs) stimulate hepatic drug metabolism in adult and developing rats. The purpose of this investigation was to determine the influence of PBBs on the development of the liver as an organ for chemical excretion. Exposure of developing rats to polybrominated biphenyls (PBBs) by feeding 50 ppm of PBBs to pregnant or lactating mothers and rat weanlings did not produce overt toxicity when compared to controls over a 49-day postnatal period. However, prenatal and postnatal dietary exposure to PBBs resulted in elevated liver weight. In 15-day-old rats, increased liver weight after PBBs was correlated with enhanced ouabain transport from plasma into bile. Liver weight was also elevated in 21-, 35- and 49-day-old rats treated with PBBs, but this effect was not associated with stimulation of ouabain transport in these animals. Stimulation of ouabain transport after PBBs in 15-day-old rats was associated with increased hepatic uptake of ouabain. Stimulation in 15-day-old rats and not older rats may be attributed to the relative importance of uptake for ouabain transport in 15-day-old rats.

Aging↗
PubMed1979

Toxicologic assessments of a commercial polybrominated biphenyl mixture in the rat.

A polybrominated biphenyl fire retardant (Firemaster FF-1) was responsible for the widespread environmental contamination and animal losses in Michigan during 1973 and 1974. In Fischer 344/N rats orally given 30,100,300, and 1,000 mg/kg (5 days/week, 22 total doses) for 4.5 weeks and observed for 90 days after the start of treatment, the LD50 was determined to be 65 mg/kg/day (total 1.43 g/kg) for the female rat and 149 mg/kg/day (total 3.28 g/kg) for the male. All female rats given the dosage of 100 mg/kg/day (22 doses, total 2.20 g/kg) died between 41 and 53 days after the start of treatment, whereas 38% of the males died between 50 and 73 days. Pathologic changes in treated rats were large liver, accentuation of the hepatic lobular markings, and atrophy of thymus and spleen. Microscopically, hepatic changes were characterized by congestion, fatty metamorphosis, and multifocal liquefactive necrosis. Male rats given 100 mg/kg/day and dying after 90 days had subacute to chronic hepatitis with marked focal proliferation of bile ducts. Exposure to Firemaster FF-1 may produce atypical liver nodules in the rat as early as 6 months after they were first given the preparation. Marked hepatotoxic effect persisted in surviving rats when examined after 6 months.

Administration, Oral↗
PubMed1977

Polybrominated biphenyls in raw milk and processed dairy products.

Milk from four dairy herds identified by the Michigan Department of Agriculture as containing less than .3 ppm (fat basis) physiologically incorporated polybrominated biphenyls was processed individually into cream, skim milk, butter, and stirred curd cheese. Pasteurized and freeze-dried whole milk, skim milk, and cream, spray-dried whole milk and skim milk, and condensed whole milk were made also. Polybrominated biphenyls were concentrated in the high-fat products. Pasteurized skim milk, buttermilk, and whey had slightly more polybrominated biphenyls than pasteurized whole milk on a fat basis. Spray-drying reduced the polybrominated biphenyls in whole milk and skim milk while pasteurization, freeze-drying, aging of cheese, and condensation were not effective.

Animals↗
PubMed1978

Formation of brominated dibenzofurans from pyrolysis of the polybrominated biphenyl fire retardant, firemaster FF-1.

The polybrominated biphenyl (PBB) fire retardant, FireMaster FF-1, was pyrolyzed for 20 min at 380-400 degrees C in open glass tubes and in tubes sealed after nitrogen flushing. The pyrolyzed residue was extracted with benzene, and extracts were cleaned up on columns of graphite (Carbopack A) and alumina. Analysis was carried out by low resolution direct probe mass spectrometry (MS). Spectra from extracts of the open tube pyrolyzed material had a series of ions characteristic of tetra- and pentabrominated dibenzofurans as evidenced by comparison with spectra from 2,3,7,8-tetrabromodibenzofuran (TBDF). Confirmatory evidence for the brominated dibenzofurans was obtained by high resolution MS dual ion analysis of certain fragment and molecular ions. Recovery values of TBDF through the cleanup procedure averaged 50% and, using this recovery value and TBDF as an external standard, dual ion analyses indicated that 40 ppm tetra- and 4 ppm pentabrominanted dibenzofuran were produced based on the PBB level used in the pyrolysis experiments. Additional analysis of the open tube pyrolyzed material by gas chromatography/mass spectrometry provided evidence that there was one tetrabromodibenzofuran compound with a retention time equal to that of TBDF. Trace levels (less than 1 ppm) of the molecular ion of tetrabrominated dibenzofuran were found after analysis by low resolution MS of the PBB pyrolyzed under nitrogen in sealed tubes. The experimental evidence is consistent with a mechanism for brominated dibenzofuran formation involving attack of oxygen on PBB compounds.

Biphenyl Compounds↗
PubMed1978

Changes in blood and urine composition from feeding polybrominated biphenyls to pregnant Holstein heifers.

The toxicity of a commercial preparation of polybrominated biphenyl was determined in 24 pregnant Holstein heifers that were alloted randomly to one of four experimental groups given 0 (I), .25 (II), 250 (III), and 25,000 (IV) mg per day of fireMaster BP-6 for 60 days or until the animals became moribund. Clinicopathologic determinations were on day -1 prior to dosing, days 15, 30 and 60 during dosing, and following dosing on days 80, 110, 150, and 190 from start of dosing. In addition, samples were collected from moribund heifers of Group IV immediately prior to necropsy. Toxicity was not evident in heifers in Groups I, II, or III. Toxicity was induced in heifers in Group IV. Glutamic-oxaloacetic transaminase of serum was increased and calcium decreased as early as day 15 whereas significant increases in lactate dehydrogenase, urea nitrogen, and bilirubin, and decreases in albumin were not observed until day 30 in heifers of Group IV. Analysis of urine from moribund heifers of Group IV revealed moderate proteinuria and decreased specific gravity. Evaluation of clinicopathologic data has suggested that the polybrominated biphenyls fed were renal toxins with no clear evidence of hepatotoxicity.

Animals↗
PubMed1978

Effect of polybrominated biphenyls on adenylate cyclase activity in rat lung alveoli.

The in vitro effect of polybrominated biphenyls (FireMaster BP-6) on adenylate cyclase [ATP pyrophosphate lyase (cyclizing), EC 4.6.1.1] activity in plasma membranes of rat lung alveoli was determined. Two fractions of plasma membranes, PM-I (approximate d = 1.13 g/cm3) and PM-II (approximate d = 1.16 g/cm3) were isolated under hypotonic homogenization and fractionation conditions (1mM NaHCO3, 5mM dithiothreitol, pH 7.5) by using differential centrifugation and nonlinear sucrose gradient centrifugation techniques. Polybrominated biphenyls (10 microgram/ml) dissolved in ethyl acetate (0.25%) stimulated basal adenylate cyclase activity of plasma membranes by 2.1 to 2.5-fold. The implication of this observation is discussed.

Adenylyl Cyclases↗