Search

1. Three main urinary metabolites, two isomers of 3-hydroxycyclohexane-1,2-dicarboximide (3-OH-HPI-1 and 2) and 1,2-tetrahydrodicarboxylic acid (TCDA) were purified from rat treated with (1RS, trans)-tetramethrin [3,4,5,6-tetrahydrophthalimidomethyl (1RS, trans)-chrysanthemate]. 2. To elucidate the mechanism of formation of these reduced metabolites, the stereochemistry of 3-OH-HPI-1, 3-OH-HPI-2 and TCDA was clarified by chemical reactions, spectroanalysis (nmr) and X-ray analysis. 3. The sole difference in configuration between 3-OH-HPI-1 and 3-OH-HPI-2 was found to be the orientation of the hydroxyl group to the cyclohexane ring, and both of these reduced metabolites showed cis-addition of two hydrogens. In contrast, reduction resulted in the trans form with TCDA. 4. These findings indicate the existence of two different reduction reaction mechanisms in the rat.

In vitro metabolism of pyriproxyfen [4-phenoxyphenyl (RS)-2-(2-pyridyloxy)propyl ether, Sumilarv] by several tissues of rats and mice was investigated. Most of the major metabolites of pyriproxyfen observed in studies of in vivo metabolism were formed by liver microsomes incubated in vitro with β-NADPH for both species. No sex-related differences were observed in mouse microsomes in major in vitro metabolic reactions, these being hydroxylation at the 4-position of the terminal phenyl ring, hydroxylation at the 5-position of the pyridyl ring, and cleavage of the propyl pyridyl or propyl phenyl ethers. On the other hand, in rat microsomes there were significant sex-related differences in these major metabolic reactions except for cleavage of the propyl phenyl ether. All of the gender-specific reactions, in which cytochrome P450 enzymes were involved, were inhibited by antisera against male-specific rat P450 CYP2C11 or CYP2C13. Therefore, the results strongly imply that the 2C family of cytochrome P450 is in...

Male rats were orally given pentyl 2-chloro-4-fluoro-5-(3,4,5,6-tetrahydrophthalimido)phenoxyacetate (flumiclorac pentyl, S-23031) labeled with 14C at 250 (mg/kg)/day for 6 consecutive days, and se...

ラット, マウス, ハムスター, ウサギおよびイヌの肝臓可溶性画分を用いて, さまざまなアニリン誘導体の in vitro におけるアセチル化の特性を明らかにした. この結果, アニリン誘導体の酵素的アセチル化にはアミノ基のオルト位置換基による立体障害および電子吸引性置換基による影響が重要であることが明らかとなった. したがって, 殺菌剤ジエトフェンカルブ (isopropyl-1,4-diethoxycarbanilate および除草剤S-23121 (N-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]-3,4,5,6-tetrahydrophthalimide のラットにおいて認められるアセチル化代謝物の産生量の差は, 生じるアニリン誘導体代謝物のアミノ基に対する立体障害によることが示唆された. また, アニリン誘導体に対する基質特異性はラット, マウス, ハムスターの間では高い相関を示したが, ウサギは他動物種とは若干異なっていた. イヌのアセチル化活性は, すべてのアニリン誘導体に対して低値を示した.

The metabolic fate of pyriproxyfen [4-phenoxyphenyl (RS)-2-(2-pyridyloxy]propyl ether, Sumilarv) was examined in rats and mice given single oral doses of [pyridyl-2,6- 14 C]- or [phenoxyphenyl- 14 C]-pyriproxyfen at doses of 2 and 1000 mg/kg. The carbon-14 was excreted almost completely into urine and feces within 7 days after dosing and fecal excretion of carbon-14 predominated in both animals. Excretion of carbon-14 into feces and urine was, respectively, 84-97% and 4-12% of the dose in rats and 64-91% and 9-38% in mice. Major metabolic reactions of pyriproxyfen were (1) hydroxylation at the 4-position of the terminal phenyl ring, (2) hydroxylation at the 2-position of the terminal phenyl ring, (3) hydroxylation at the 5-position of the pyridyl ring, (4) dephenylation, (5) cleavage of ether linkages, and (6) conjugation of the resultant phenols with sulfuric acid or glucuronic acid. Although there was generally no marked difference in the metabolic profile of pyriproxyfen between the two species, significant sex-related differences were found in metabolic reactions 1, 3, and 6 in the rat but not in the mouse.

We examined whether the repeated oral administration with a high dose of l -3-(3,4-dihydroxyphenyl)-alanine ( l -DOPA) in 0.5% carboxymethyl cellulose increases serum luteinizing hormone (LH) levels in male rats. Serum LH levels were increased 4 h after a single administration of 1000 mg/kg l -DOPA to male rats, and returned to control levels within 8 h after administration. Four hours after a single administration, serum LH levels were significantly increased by l -DOPA at 1000 mg/kg, but not at 20, 100 or 200 mg/kg. Decreases in body weight and relative weight of the prostate were observed after 7 and 14 days of administration of 1000 mg/kg per day l -DOPA, but no changes were observed in weight of the testis, epididymis or seminal vesicle. The administration of l -DOPA at 500 or 1000 mg/kg per day for 7 or 14 days resulted in increased basal serum LH levels and decreased basal serum prolactin levels 24 h after the last administration. Serum testosterone levels tended to be higher in treated than in control rats. The levels of two metabolites of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in rats treated with 500 mg/kg per day tended to be slightly higher than those in control rats after 7 days of administration. Levels of DA, DOPAC and HVA were significantly increased after 7 and 14 days of administration of 1000 mg/kg per day and after 14 days of administration of 500 mg/kg per day. The level of norepinephrine, but not its metabolite 3-methoxy-4-hydroxyphenylglycol, was significantly increased after only 7 days of administration of 1000 mg/kg per day. No significant changes were observed in levels of 5-hydroxytryptamine or its metabolite 5-hydroxyindole-3-acetic acid with administration of 500 or 1000 mg/kg per day. These findings suggest that a prolonged treatment with a high dose of l -DOPA in male rats induces release of LH from the pituitary, resulting in sustained elevation of LH levels in peripheral circulation.

Male and female rats were given a single oral dose of [phenoxyphenyl- 14 C]pyriproxyfen [4-phenoxyphenyl (R,S)-2-(2-pyridyloxy)propyl ether] at 2 (low dose) or 1000 (high dose) mg/kg. 14 C was rapidly excreted into feces and urine, with the former route predominating (about 90% of the dose). Peak 14 C concentrations in blood, kidney, liver, and other tissues except for fat occurred 2-8 h after administration, being 0.4, 0.4, 2.5, and

Studies were performed to examine the mechanism by which testicular Leydig cell tumors are induced in rats by administration of the antimicrobial agent oxolinic acid (1-ethyl-1,4-dihydro-6,7-methylenedioxy-4-oxo-3-quinolinecarboxylic acid). In these studies, the effects of oxolinic acid on serum levels of luteinizing hormone (LH), testosterone, and prolactin and the binding of testosterone to prostatic androgen receptors were examined. In a long-term hormonal study, male Wistar rats were fed a diet containing oxolinic acid at 0, 100, 1000, or 3000 ppm for 104 weeks. A statistically significant increase in serum LH levels was observed at 1000 and 3000 ppm, but no dose of oxolinic acid had a significant effect on serum testosterone levels. Serum LH levels were no longer elevated above control levels within 2 weeks of cessation of the administration of oxolinic acid. Oxolinic acid was found to have no effect on the rate of clearance of exogenous LH from the circulation. Serum prolactin levels were decreased by the administration of oxolinic acid. The increase in serum LH induced by oxolinic acid was completely blocked by the intraperitoneal injection of the dopamine antagonist haloperidol (2 mg/kg). In addition, no significant affinity of oxolinic acid for androgen receptors was found in an in vitro study. These findings suggest that: (1) oxolinic acid induces Leydig cell tumors in rats by chronically stimulating the release of LH from the pituitary, (2) the mechanism of stimulating the release of LH involves facilitation of the dopaminergic systems in the hypothalamus-pituitary axis, and (3) oxolinic acid has no effect on androgen-mediated feedback inhibition.

1. Urinary and faecal metabolites in rat treated with 14C-labelled (1RS, trans)-tetramethrin [3,4,5,6-tetrahydrophthalimidomethyl (1RS, trans)-chrysanthemate] were identified using chromatographic techniques and spectroanalyses (nmr and ms). 2. 3-Hydroxy-cyclohexane-1,2-dicarboximide was found to be a major and unique urinary metabolite, reduced at the 1,2-double bond of the 3,4,5,6-tetrahydrophthalimide moiety. 3. The major faecal metabolites were sulphonic acid conjugates, having a sulphonic acid group incorporated into the double bond of the 3,4,5,6-tetrahydrophthalimide moiety. 4. On the basis of the metabolites identified here, the major biotransformation reactions of trans-tetramethrin in rats are: (1) cleavage of the ester linkage; (2) cleavage of the imide linkage; (3) hydroxylation of the cyclohexene or cyclohexane ring of the 3,4,5,6-tetrahydrophthalimide moiety; (4) oxidation at the methyl group of the isobutenyl moiety; (5) reduction at the 1,2-double bond of the 3,4,5,6-tetrahydrophthalimide moiety; and (6) incorporation of a sulphonic acid group into the 1,2-double bond of the 3,4,5,6-tetrahydrophthalimide moiety.

1. To examine the metabolic fate of N-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]-3,4,5,6- tetrahydrophthalimide (S-23121), rats were given a single oral dose of [phenyl-14C]S-23121 at 1 or 250 mg/kg. 2. The radiocarbon was almost completely eliminated from the rat within 7 days after administration for both dose groups. Faecal 14C-excretion was major (71-86% of the dose) and urinary 14C-excretion was minor (18-30%). 3. 14C-tissue residues on the seventh day after administration were generally very low. Peak 14C-concentrations in the kidney and liver occurred 4 h after administration and decreased rapidly thereafter. Amounts (percentage of dose) of the parent compound in faeces were 13-26% for low dose, and 22-35% for high dose. 4. The major metabolites in faeces were sulphonic acid conjugates (13-20% of the administered dose), formed by incorporation of a sulphonic acid group into the double bond of the tetrahydrophthalimide. The major metabolites in urine were sulphates and glucuronides of 4-chloro-2-fluoro-5-hydroxyaniline, amounting to 5-7 and 2-3% of the administered dose, respectively. Sulphonic acid conjugates were not detected in urine, blood, kidney or liver.

Effects of alpha 2u-globulin accumulating agents on alpha 2u-globulins in rat kidneys were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting analysis. Treatment of male animals with decalin (150 mg/kg), 2,2,4-trimethylpentane (50 mg/kg), isophorone (150 mg/kg), d-limonene (150 mg/kg) or 1,4-dichlorobenzene (150 mg/kg) by gavage for 14 consecutive days in each case resulted in a marked intensification of a protein band corresponding to kidney-type-alpha 2u-globulin, with a molecular mass calculated to be approximately 16 kDa. However, intraperitoneal treatment with leupeptin and E-64 (two times 0.07 mmol/kg, for each), well known cystein protease inhibitors, while only slightly increasing this kidney-type-alpha 2u-globulin band, caused the intensification of a approximately 19-kDa molecular mass protein band which was revealed to be a native-type-alpha 2u-globulin by SDS-PAGE and immunoblotting. These results indicated that at least two types of alpha 2u-globulin can be increased in male rat kidney by chemical treatment. Moreover, cystein protease(s) appear(s) to play an important role in the degradation of alpha 2u-globulin and particularly in the conversion of native-type-alpha 2u-globulin to kidney-type-alpha 2u-globulin in rat kidneys.

1. Acute toxicity: Empenthrin ((RS)-(EZ)-1-ethynyl-2-methyl-2-pentenyl (1R)-cis/trans-chrysanthemate) caused some toxic signs such as muscular fibrillation, tremor, hypersensitivity, decrease of spontaneous activity, ataxic gait, lymb paralysis, irregular respiration, excretion of oily substance, loose stool and urinary incontinence in oral acute toxicity studies at 1000 mg/kg and above in rats, and at 2000 mg/kg and above in mice. The oral LD50 value was estimated greater than 5000 mg/kg (male) and greater than 3500 mg/kg (female) in rats and greater than 3500 mg/kg (both sexes) in mice. In both rats and mice, the toxic signs were not found at 2000 mg/kg by dermal administration. The dermal LD50 value was estimated greater than 2000 mg/kg (both sexes) in both rats and mice. The LC50 value in rats for the acute inhalation toxicity of empenthrin was estimated to be greater than 4610 mg/m3 for both sexes. The LC50 value in mice was determined to be 2700 mg/m3 for male and 2300 mg/m3 for female. Mice showed higher sensitivity to empenthrin than rats. 2. Reproductive and developmental toxicity: Empenthrin was orally administered to fetal organogenesis periods of rats at the dose levels of 50, 150 and 500 mg/kg, and of rabbits at 100, 300 and 1000mg/kg. Maternal toxicity was found at 500 mg/kg in rats and at 300 mg/kg or more in rabbits. There were no teratogenicity, no embryotoxicity and no fetal retardation in rats or rabbits. In addition, there were no adverse effects on F1 pups growth, development or reproductive performance. 3. Subchronic toxicity: Empenthrin was orally administered to male and female SD rats at dose levels of 0 (corn oil), 10, 100 and 300 mg/kg for 26 weeks. Clinical signs, body weight, food and water consumption were monitered, and hematological, blood biochemical, ophthalmological and histopathological examination were carried out. As a result, changes related to administration of empenthrin were observed mainly in the liver and kidneys in rats receiving 100 mg/kg or more. Therefore, the no-effect-level of empenthrin is determined to be 10 mg/kg in both sexes of rats in this study.

ピレスロイド系殺虫剤の光学異性体 (4異性体: パーメスリンとフェンバレレート, 8異性体: サイパーメスリンとデルタメスリン) とフェンプロパスリンの土壌中での分解速度および経路について比較検討した. 畑地状態の土壌中ではトランス異性体はシス異性体より, またαS異性体はαR異性体より速く分解した. 土壌中ではシス/トランス, αS/αRの異性化は認められなかった. 各異性体の半減期の最大値および最小値で土壌中での分解速度を比較すると, パーメスリン>サイパーメスリン≒デルタメスリン>フェンプロパスリン>フェンバレレートの順であった. 分解の速いトランスあるいはαS異性体を添加した土壌では14CO2とエステル結合開裂物が多く生成し, 分解の遅いシスあるいはαR異性体を添加した土壌では環水酸化物およびジフェニルエーテル結合開裂物が多く生成した. 菊酸のジクロルビニル類縁体の4異性体の土壌中での分解速度も比較検討した.

ピレスロイド系殺虫剤の光学異性体 (4異性体: フェンバレレート, 8異性体: サイパーメスリン) の土壌微生物による分解について検討した. 土壌より単離した細菌によるピレスロイドの分解は異性体により差が見られ, 培養液中にはエステル結合加水分解物が主に検出された. 単離菌の無細胞抽出液をゲル濾過して得られた各画分について各異性体の分解を検討したところ, 基質特異性の異なる活性ピークが数ピーク認められた. 土壌微生物には基質特異性の異なる複数のピレスロイド加水分解酵素が存在し, 土壌中で各異性体の分解速度に差が生じることが示唆された.

To examine the mechanism and toxicological significance of thyroidal tumor observed slightly in a long-term rat study with diethofencarb (isopropyl 3, 4-diethoxycarbanilate), male Sprague-Dawley rats were fed diethofencarb in diets at concentrations of 0, 5, 000 or 20, 000 ppm for 3 months. Examinations mainly for thyroid functions including thyroid uptake of &lt125&gtI, serum thyroid hormone and thyroid stimulating hormone (TSH) level, hepatic UDP-glucuronyltransferase (UDP-GT) activity and histopathological examination in thyroid were performed at week 13. Decreases of body weights and food consumptions were observed at and above 5, 000 ppm. Under these conditions, decrease of serum free T4 and increase of serum TSH level were observed only at 20, 000 ppm, concurrently with liver weight increase at and above 5, 000 ppm and increase of hepatic UDP-GT activity at 20, 000 ppm. However, no compound related effects were noted in thyroid weight, thyroid uptake of &lt125&gtI and gross or histopathological examination in thyroid. These results indicate that the administration of diethofencarb leads to an increase in UDP-GT activity and acceleration of thyroid hormone excretion from the liver. The acceleration causes a decrease in serum free T4 level, triggering the feedback mechanism of the pituitary gland, promotion of TSH release and consequently an increase in serum TSH level. Thus, the slightly higher incidence of thyroid follicular cell tumors observed in the chronic and oncogenicity study with non-genotoxic diethofencarb is considered to be caused by these weak pituitary-thyroid hormonal imbalances. The toxicological significance in humans is extremely low according to the well established facts that the chronic TSH stimulatin would not induce thyroid tumors in humans and humans may be less sensitive than rats in regard to the response to goitrogenic stimuli.

Induction of hepatic UDP-glucuronyltransferase(s) (hUDP-GT(s] activity toward thyroid hormones and the relationship between the activity and the serum thyroid hormones or the thyroid stimulating hormone (TSH) level were examined in male Sprague-Dawley rats after four consecutive ip doses of various hepatic enzyme inducers at 75-150 mg/kg/day. hUDP-GT activity toward thyroxine (T4; hUDP-GT-T4) was induced by treatment with beta-naphthoflavone, 3-methylcholanthrene (3-MC), polychlorinated biphenyls, or pregnenolone-16 alpha-carbonitrile. However, no significant induction was observed for isosafrole administration and in the cases of phenobarbital and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane slight decreases were found. The induction profile of hUDP-GT-T4 for these inducers was approximately the same as that of hUDP-GT activity toward triiodothyronine (T3; hUDP-GT-T3), indicating that these two thyroid hormones (T4 and T3) are glucuronidated by the same hUDP-GT(s). Moreover, the induction profile of both hUDP-GT-T4 and hUDP-GT-T3 was similar to that of hUDP-GT toward 1-naphthol, but not chloramphenicol, suggesting that T4 and T3 belong to the so-called group-1 substrates which are preferentially glucuronidated by hUDP-GT(s) inducible by treatment with 3-MC. Decreases in serum T4 levels clearly correlated with an increase in hUDP-GT-T4 activity, indicating that serum T4 levels are directly affected by hUDP-GT-T4 activity. However, no direct correlation between decrease in thyroid hormone levels and compensatory increase in TSH levels was found.

プロシミドン [N-(3,5-dichlorophenyl)-1,2-dimethyl-cyclopropane-1,2-dicarboximide] のラットおよびマウスにおける代謝運命を比較検討した. 14C標識体を100mg/kgの投与量で1回経口投与したところ, 投与14Cは, 両種とも投与後7日以内にほぼ完全に排泄され, 主要排泄経路は尿であった. 血中14C濃度は, 投与後2から12時間でプラトー状態を示した. ラットでは12時間で, マウスでは2時間で最高値に到達した. 投与後8時間から72時間までラットで生物学的半減期12時間, マウスでは10時間で減少した. 排泄物および組織中の同定代謝物からプロシミドンのラットおよびマウスにおける主要代謝反応は, メチル基のヒドロキシメチルを経由したカルボン酸への酸化およびイミド結合の開裂であった. プロシミドンの代謝において顕著な種差は認められなかった.

A sensitive method using selective plating media to detect a genetically engineered microorganism (GEM) released into the environment was developed. In experiments, a strain of Pseudomonas sp. capable of assimilating monofluoroacetate (FA) as a sole carbon source was chosen as the GEM model. Two sorts of Japanese paddy soil were used as a microcosm. In a trial when serial 10-fold soil dilutions were spread on minimal FA agar plates and incubated, native oligotrophic microorganisms (105-106CFU/g of dry weight of soil) grew on the plates. So, it was difficult to pick out a few populations of target bacteria from such a high number of background microbial communities. A further examination showed that those indigenous microorganisms colonized even on plates containing only water and agar. For this reason, we tested silica-gel instead of agar as an agent to solidify the selective media. On minimal FA silica-gel plates, the number of indigenous oligotrophic colonies was greatly decreased. When a definite number of target Pseudomonas cells was mixed with the soil dilutions and cultured on minimal FA silica-gel plates, only the target colonies were appeared. We applied the most-probable-number technique to the plate-counting method to attain as low as 4CFU/g of dry weight of soil as the statistical limit of detecting FA-assimilating bacteria. This selective plating method is suitable for environmental monitoring of GEMs which assimilate FA aerobically, as it is on highly sensitive, specific and feasible.

The temperature-dependent terms are introduced into modified fugacity models for aerial application of pesticides to predict temperature-dependent changes of the pesticide fate. In a simulation, temperature is varied from 18°C to 30°C and from 30°C to 18°C per 24 hours. The model describes the concentration of the released pesticide in air as a fuction of temperature. The calculated profiles are consistent with the data measured for Pesticide S in the field. The results suggest that the model is useful for predicting the temperature-dependent changes in behavior of the pesticide in aerial application.

A total synthesis of (+)-aste1toxin, a novel mycotoxin isolated from Aspergillus stellatus, has been achieved by using D-glucose as an enantiomerically pure starting material.

ピレスロイド系殺虫剤フェンプロパスリンのシクロプロパン環もしくはベンジルフェニル環を14Cで標識した化合物を用いて, 土壌中での分解とリーチングについて検討した. 2種類の土壌に1ppmの割合で添加して好気的畑地条件に保つと, 消失半減期が11～17日の速度で分解した. おもな分解経路はエステル結合の加水分解で, 他にジフェニルエーテル結合の開裂, フェニル環の水酸化, シアノ基の加水分解をうけ, 生成した分解物はさらに14CO2まで分解したり bound 14Cを形成した. Bound 14Cは生土と混合すると一部が14CO2まで分解した. フェンプロパスリンは嫌気条件の畑土壌では分解は遅く, 滅菌条件ではほとんど分解しなかった. またフェンプロパスリンは処理直後および4週間のインキュベート後に拘わらず, 畑土壌からリーチングしなかった.

14C-フェニトロチオンマイクロカプセル及び14C-クロルデンを経口投与した場合のコイにおける挙動について検討した。クロルデンは魚体中の主にCarcassに移行・蓄積し,水中への排泄はほとんど認められなかったのに対して,フェニトロチオンマイクロカプセルの場合は,24時間後には投与14Cの96.9%が水中に排泄された。排泄された14Cの大部分はマイクロカプセル内のフェニトロチオンであり,フェニトロチオンは魚体中に吸吸されることなく,そのまま排泄されることが明らかとなった。

A Level IV fugacity model was modified to build up a new one for aerial application of pesticides. The fugacity model developed by Mackay et al. can well describe the environmental fate of chemicals. However, the model is not applicable to non-gaseous chemicals, such as pesticides, when they are released directly into the atmosphere. This is because of a limiting assumption in the model that these chemicals must be instantaneously and evenly distributed in the atmosphere after the release, which is far different from actual observations. For the purpose of developing a suitable model for aerial application of pesticides to a forest, a new pesticide “droplet” compartment together with a “forest” one was introduced into the fugacity model; where the droplets with time, absorbed into forest, water and soil (the “spray zone”). The model was further expanded to describe the pesticide fate outside the “spray zone”. For the modelling, a typical land of square 10 km with atmosphere above is used as an environment. “Spray zone” with area of square 1 km is located in the center of the land and the surrounding land is divided into nine “adjacent zones” by a 500 m interval. Each “adjacent zone” has six compartments insides; air, water, soil, bottom sediment, suspended sediment and aquatic biota. When sprayed pesticide drifts to the “adjacent zones”, the “droplet” compartment, which has been generated in the “spray zone”, is added to the zones as a 7th compartment (the “adjacent zones”). A numerical solution of kinetics equations was made for the pesticide behavior in the “spray zone” and the “adjacent zones” in aerial application.

1. To examine the metabolic fate of Cyanox [O-4-cyanophenyl O, O-dimethyl phosphorothioate, cyanophos, CYAP], rats of both sexes were administered [phenyl-4C]Cyanox as a single oral dose at levels of 0.5 mg/kg (low-dose group) or 25 mg/kg (high-dose group), or as multiple doses at 50 mg/kg/day once daily for 7 days (repeat-dose group). 2. The radiocarbon was almost completely eliminated from rats within 7 days after administration in both low- and high-dose groups. 14C-recoveries (expressed as % relative to the dosed 14C) in faeces and urine were 2-3 and 95-96% respectively for the low-dose and 13-14 and 86% respectively for the high-dose. 3. 14C-tissue residues on the seventh day after a single administration were generally low. Peak 14C-concentrations in blood and kidney occurred at 0.5 h (high-dose) and decreased rapidly thereafter. 4. Sex-related differences in the amounts of metabolites were observed in both groups. With the low-dose, the major metabolite was 4-cyanophenylsulphate in both sexes. However, in the high-dose, the major metabolites were 4-cyanophenyl sulphate and desmethylcyanoxon in males, but 4-cyanophenyl sulphate and desmethylcyanox in females. These findings indicate that the amounts or the types of enzymes responsible for oxidative desulphuration or oxidative dearylation in males are different from those in females. In the male rat given repeat doses significant differences in the amounts of metabolites in excreta were observed between early and final dosing. 5. The greater formation of desmethylcyanoxon in the male rat in the high-dose case is consistent with the higher incidence of toxicity in this sex.

Oxolinic acid (1-ethyl-1,4-dihydro-6,7-methylenedioxy-4-oxo-3-quinolinecarboxylic acid), an antimicrobial agent, raises the serum levels of luteinizing hormone (LH) and increases the incidence of testicular Leydig cell tumors in male rats. In the present study the mechanism by which serum LH levels are raised in male rats receiving oxolinic acid was investigated. Aged Wistar rats were fed a diet containing oxolinic acid at 0 or 3000 ppm for more than 4 weeks. There was no effect of oxolinic acid on either the maximal levels of serum LH after castration nor on the serum levels of LH stimulated with 1 μg/rat of luteinizing hormone-releasing hormone (LHRH). The concentrations of testosterone in serum and testis were not changed by the treatment of oxolinic acid. In the in vitro organ culture, the testes of rats receiving oxolinic acid released testosterone in the same manner as the controls, in the presence or the absence of human chorionic gonadotropin (100 mIU/ml). The oxolinic acid-stimulated serum LH was not increased further by the daily administration of L-dopa (500 mg/kg/day, po, 7 days) and was blocked by the injection of a dopamine antagonist, haloperidol (2 mg/kg, ip). In a microdialysis study, oxolinic acid increased the extracellular concentration of dopamine in the preoptic area of hypothalamus. These findings suggest that a high dietary level of oxolinic acid elevates LH release from the anterior pituitary with an increase in LHRH, in part, by the excitatory input of a dopaminergic system in the preoptic area of rat hypothalamus.

To clarify the mechanism of species difference in the induction of testicular interstitial cell tumor (ICT, Leydig cell tumor) between rats and mice, male Sprague-Dawley rats and ICR mice were fed procymidone at dietary concentrations of 700, 2000 or 6000 ppm and 1000, 5000, or 10,000 ppm, respectively, for 3 months. The Leydig cell functions were evaluated by serum testosterone and luteinizing hormone (LH) levels, testosterone levels in the testis, LH levels in the pituitary, the capacity of the testis to respond to gonadotropin stimulation, i.e., the production of testosterone in vitro, and by the testicular binding of labeled human chorionic gonadotropin (hCG). Measurement of testosterone and LH levels in rat serum, the testis, or the pituitary showed that both hormones were enhanced throughout the 3-month treatment period. The hypergonadotropism was associated with the increase of interstitial cell response to hCG in vitro for up to 3 months. As with rats, both serum and pituitary LH were increased in mice at 4 weeks but not at 13 weeks. However, in contrast to rats, no significant increase in testosterone was observed in mice either in vivo or ex vivo during the course of the study. This suggests a difference between the rat and mouse in the response of the Leydig cell to the LH stimulation associated with procymidone administration. These differences in the response of interstitial cells to procymidone may be the basis for the distinct species responses to procymidone-induced Leydig cell tumorigenesis. The sustained response of the Leydig cells to stimulation in the rat results in chronic hyperplasia and subsequent benign tumor formation, while the attenuated response of Leydig cells in the mouse is associated with neither hyperplasia nor neoplasia.

1. To examine the metabolic fate of (1RS, trans)- or (1RS, cis)-tetramethrin [3, 4, 5, 6-tetrahydrophthalimidomethyl (1RS, trans)- or (1RS, cis)-chrysanthemate], rat was administered a single oral dose of trans- or cis-[alcohol-14C]tetramethrin at dose levels of 2 or 250 mg/kg. 2. The radiocarbon was almost completely eliminated from rat within 7 days after administration in all groups. 14C-recoveries (expressed as percentages relative to the dosed 14C) in faeces and urine were 38-58 and 42-58% respectively in rat administrated trans-[alcohol-14C]tetramethrin, and in faeces and urine were 66-91 and 9-31% respectively in rat administered cis-[alcohol-14C]tetramethrin. 3. Fourteen metabolites found in excreta were purified by using several chromatographic techniques and identified by spectroanalyses (nmr and MS). Five sulphonate derivatives and three dicarboxylic acid derivatives were found. 4. The main metabolites were sulphonate derivatives in the faeces, and in the urine, alcohols, dicarboxylic acid and reduced metabolites derived from the 3,4,5,6-tetrahydrophthalimide moiety.

1. Two major metabolites of 14C-labelled (4S,1R)-trans-Etoc[(S)-2-methyl-4-oxo-3-(2-propynyl)cyclopent-2-enyl (1R)-trans-chrysanthemate] were purified using a combination of chromatographic techniques and identified by spectroanalysis (nmr(HMBC) and FAB-, TSP-MS). These were established as new types of S-linked conjugates (sulphonic acid and mercapturic acid types). 2. To examine the mechanism of formation of the sulphonic acid and mercapturic acid conjugates, sodium sulphate or glutathione labelled with 35S were administered to rat along with unlabelled trans-Etoc. Both sulphonic acid and mercapturic acid conjugates were found in the excreta, more of the former being yielded with 35S-sodium sulphate than with 35S-glutathione, implying that a sulphonic acid was incorporated into the double bond of a possible intermediate after reduction of sulphate to sulphite. The mercapturic acid conjugate was produced only with 35S-glutathione, implying incorporation of glutathione into the triple bond before subsequent generation of mercapturic acid from the glutathione conjugate. 3. Additional investigation of whether or not the mercapturic acid conjugate was produced by mixing the alcohol moiety of Etoc, PGL (4-hydroxy-3-methyl-2-(2-propynyl)cyclopent-2-en-1-one) and N-acetyl-L-cysteine under alkaline conditions. However, spectral data for the synthesized compound were not the same as those of the metabolite generated in vivo. That is, the addition reaction appeared to proceed by anti-Markownikov's rule, whereas the in vivo metabolite was apparently formed according to Markownikov's rule. Addition of glutathione at a triple bond has not been reported to our knowledge for any other foreign compounds in mammalian species.

A chronic feeding study was conducted to determine the carcinogenic potential of oxolinic acid, an antimicrobial agent, in rats and mice. Oxolinic acid was administered in the diet to Wistar rats (0, 30, 100, 300 or 1000 ppm; 50 rats/dose/sex) for 104 wk and to ICR mice (0, 50, 150 or 500 ppm; 50 mice/dose/sex) for 78 wk. Clinical signs, body weight, food consumption, autopsy findings and histopathological data were noted. Mortality was unaffected by oxolinic acid administration in neither species. In rats, body weight gain was suppressed in both sexes at 1000 ppm. Histopathological examinations conducted after autopsy at 104 wk revealed a slight increase in benign Leydig cell tumours of the testis at 1000 ppm. which did not appear until late in the lifetime of rats. No other treatment-related neoplastic lesions were observed in rats. Non-neoplastic lesions in males at 1000 ppm included Leydig cell hyperplasia and tubular atrophy of the testes. In mice, decreased body weight gain was observed in both sexes at 500 ppm, but no non-neoplastic or neoplastic lesions attributable to the treatment with oxolinic acid occurred in either sex. In conclusion, oxolinic acid induced benign Leydig cell tumours of the testis in rats at the highest dose level tested (1000 ppm). The no-effect level for tumour induction was confirmed to be 300 ppm (10.9 mg/kg/day) in rats. None was induced in mice.

To clarify the mechanism of gonadotropin imbalances and the differential response of rat and mouse testicular interstitial cells (Leydig cells) to procymidone, N-(3,5-dichlorophenyl)-1,2-dimethylcyclopropane-1,2-dicarboximi de, male Sprague-Dawley rats and ICR mice were fed procymidone in diet for 2 weeks at 0, 700, 2,000 and 6,000 ppm for rats, or 0, 1,000, 5,000 and 10,000 ppm for mice. Testosterone and luteinizing hormone (LH) levels in serum, testis or pituitary and the in vitro binding affinities of procymidone, flutamide and related compounds to the androgen receptor in prostate cytosol of rats and mice were examined. Hypergonadotropism in rats and mice was clearly observed in the same order two weeks after the initiation of treatment with procymidone. Increased levels of testosterone and LH in serum at 6,000 ppm and LH in pituitary at and above 700 ppm in rats were observed. In mice, testosterone levels in serum and testis elevated at 10,000 ppm. LH levels in serum and pituitary elevated significantly as well at around 5,000 to 10,000 ppm. In the competitive binding assay, procymidone showed a significant but lower binding affinity comparing to that of cyproterone acetate, the steroidal androgen receptor antagonist, for the androgen receptor in both rats and mice under the condition that unlabeled dihydrotestosterone (DHT) effectively inhibited the binding of [3H]-DHT to the androgen receptor in both species. The relative binding affinity (RBA) of procymidone was of the same order as that of flutamide, a synthetic non-steroidal antiandrogen structurally similar to procymidone. These results indicate that procymidone is an active antiandrogen and the androgen receptor antagonism is the likely mechanism of action.

To investigate the mechanism and toxicological significance of testicular interstitial cell tumors (ICT) observed in a long-term rat study with procymidone, N-(3, 5-dichlorophenyl)-1, 2-dimethylcyclopropane-1, 2-dicarboximide, male Sprague-Dawley rats were fed procymidone in diets for up to 6 months with a positive control group receiving a single subcutaneous injection of cadmium chloride. Examinations mainly for gonadal functions such as serum testosterone and luteinizing hormone (LH), reproductive organ weight and histopathology presented evidence of the indirect involvement of gonadotropins in the production of ICT in rats. A significant increase in both serum testosterone and LH was observed in the early stage at high dietary concentrations of procymidone without any lesion in gonadal systems in histopathology, whereas administration of cadmium chloride produced the expected substantial increase in serum LH and a concomitant decrease in serum testosterone with a marked damaging effect on gonadal systems. Increases in serum testosterone and LH levels in animals receiving procymidone were reversible. The no-effect level for procymidone on serum testosterone and LH was 300 ppm over six months of treatment. The possible mechanism of ICT production in rats by non-genotoxic procymidone, structurally similar to flutamide, a synthetic non-steroidal antiandrogen, is likely to be derived from its induction of a hypergonadotropism due to the competitive binding to the androgen receptor, preventing the normal effect of testosterone to control the circulating level of LH.

To assess the toxicological significance of thyroidal tumor observed slightly in a long-term rat study with diniconazole, (E)-1-(2, 4-dichlorophenyl)-4, 4-dimethyl-2-(1, 2, 4-triazol-1-yl)-1-penten-3-ol, a 3-month subacute feeding study was conducted in male Crj: CD (SD) rats by administering diniconazole in diet at concentrations of 0, 100, 1, 000, or 2, 000 ppm. Examinations mainly for thyroid functions were performed at Weeks 2, 4 and 13. Measurement of serum hormone levels revealed continuous decreases in serum thyroxine (T4) and free T4 levels at and above 1, 00 ppm and increase in serum thyroid stimulating hormone (TSH) level at 2, 000 ppm concurrently with liver weight and hepatic UDP-glucuronyltransferase (UDP-GT) increases at and above 1, 000 ppm. No changes were observed in serum triiodothyronine (T3) and free T3 levels. Increase in thyroid uptake of &lt125&gtI and organification of &lt125&gtI in the thyroid at 2, 000 ppm and thyroid follicular cell hyperplasia at and above 1, 000 ppm were also observed. However, no compound-related changes were observed in autopsy and organ weight in the thyroid. Based on the above results, diniconazole induces increases in the hepatic UDP-GT activity and the thyroid hormone excretion from the liver. The increased excretion of thyroid hormones causes decrease in serum T4 and free T4 levels, triggering the feedback mechanism of the pituitary gland, promotion of TSH release from the pituitary gland and increase in serum TSH level. The increased serum TSH level probably leads to increased &lt125&gtI uptake of thyroid and thyroid follicular cell hyperplasia. Thus, the thyroid tumorigenesis in rats treated with diniconazole is due to the secondary overstimulant effect on the thyroid by increased serum TSH level. The toxicological significance in humans is extremely low and it is unlikely that diniconazole would increase thyroid tumor in humans even if diniconazole were to alter normal thyroid hormone level in humans.

ピレスロイド系殺虫剤フェンバレレートの酸およびアルコール側のフェニル基を14Cで標識した化合物を新たに用いて, 土壌中での分解についてさらに検討を加えた. フェンバレレートを2種類の土壌に1ppmの割合で添加して好気的畑地条件に保つと, 酸化および加水分解を経て初期消失半減期が3週と16週の速度で分解し, 48週後には0.03ppmと0.29ppmに減少した. 主分解経路はエステル結合の加水分解で, 生成した3-phenoxybenzoic acid と2-(4-chlorophenyl)-3-methylbutyric acid はさらに環の開裂を受けて最終的にCO2 (添加14Cの25～66%) にまで分解した. また, 分解物としてα-carboxy-3-phenoxybenzyl 2-(4-chlorophenyl)-3-methylbutyric acid が新たに同定された. フェンバレレートから生成した bound 14C を含む土壌抽出残渣に新鮮な土壌を加えてインキュベートすると14CO2が発生し, その割合は24週間後に bound 14Cの18～24%に達した.

The hydrolysis of [14C] fenpropathrin (I) [(RS)-α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate] was studied in buffer solutions at pH 1.9–10.4, and in natural river and sea water at 25, 40, 55 and 65°C under laboratory conditions. The hydrolysis of I proceeded predominantly through neutral (pH independent) and base-catalysed processes in the regions below pH 3.9 and above pH 7.0, respectively, whereas both reactions occurred between pH 3.9 and 7.0. The rates of hydrolysis of I in buffer solutions were similar to those in one sample of river and one sample of sea water. If this obtains generally, it may be expected that the half-life of I in natural waters, normally within the range pH 5–9, will range from 1.54 to 1080 days at 40°C, 11.3 to 8520 days at 25°C and, by extrapolation of the data obtained in buffer solutions, 106 to 83 000 days at 10°C. The rate constants for hydrolysis of I in aqueous media can be expressed by: Where log kN = 9.60–(5.56 × 103 T−1) and log kB = 7.32–(2.56 × 103 T−1). The calculated rate constants were in good accord with the observed values in buffer solutions. Cleavage of the ester linkage was more rapid than hydration of the cyano group at any pH and temperature tested.

Upon single oral administration to rats, the mono-, di- and tri-glucose conjugates of [14C]-3-phenoxybenzyl alcohol (I) or the mono-glucose conjugate of [14C]-3-phenoxybenzoic acid (II) were rapidly hydrolysed and extensively eliminated in the urine mostly as the sulphate conjugate of 3-(4-hydroxyphenoxy)benzoic acid (X). The faecal elimination was a minor route, whereas the biliary excretion was about 42% of the dose and the glucuronide conjugates of I, II and X were common major metabolites. The biliary glucuronides were cleaved in the small intestine to the respective aglycones, which were reabsorbed, metabolised further, and excreted in the urine as the sulphate conjugate of X. Although small amounts of the mono-, di-and tri-glucosides were found in the 0.5-h blood and liver samples following oral administration of the tri-glucoside of I, they were not detected in the urine, bile or faeces. Similarly the sulphate conjugate was one of the major urinary metabolites of germ-free rats, dosed with the 14C-glucosides via the oral or the intraperitoneal route, although they were excreted unchanged in certain amounts in the urine and faeces. The glucose conjugates were cleaved in vitro by gut microflora and in various rat tissues, including blood, liver, small intestine and small intestinal mucosa. The tissue enzymes showed a different substrate specificity in hydrolysis of the glucosides. However, they were not cleaved in gastric juice, bile, pancreatic juice or urine.

Using a spin-trap reagent 3-nitrosodurene (1,2,4,5-tetramethyl-3-nitrosobenzene), the short-lived free radicals generated by ultraviolet irradiation of fenvalerate [(RS)-α-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] in degassed benzene or dichloromethane, were scavenged as the more stable nitroxide radicals. These radicals were separated by high-performance liquid chromatography and identified individually by electron-spin resonance spectroscopy, as well as by gas chromatography/mass spectrometry. As a result, they were found to be the spin adduct mixtures of the 4-chloro-α-isopropylbenzyl and α-cyano-3-phenoxybenzyl radicals, which are involved in the photo-induced decarboxylation process of fenvalerate. Discrimination of the radicals was also performed by the isotope-labelling method whereby the benzylic proton in the acid moiety was deuteriated. The spin numbers of the nitroxides decreased by about five-fold when photolysis was carried out in oxygenated benzene solution. N-Benzylidene-tert-butylamine N-oxide trapped both radicals but much less efficiently. The nitroxide of the 4-chloro-α-isopropylbenzyl radical was predominant at 25°C or –40°C, but the proportion of the α-cyano-3-phenoxybenzyl nitroxide radical increased at the lower temperature.

ヒメダカの胚から成魚に至るに発育段階に対するフェニトロチオンの急性毒性試験を行なったところ, 後期仔魚II期 (孵化後28日目) が, 最も感受性が高く, 胚期が最も感受性が低く, おのおのの96hr LC50値は2.36ppm, 10ppm以上であった. 毒性発現をコリンエステラーゼ活性およびオキソンによる阻害濃度 (I50) との関係で調べると, 活性は胚期で弱く, それ以降ではほぼ一定であったが, I50は成魚で最も低い値 (5μM) を得た. DDTでは, フェニトロチオンと同様な発育段階と毒性との関係が得られたが, その関係は顕著であり, また胚期, 前期仔魚期に暴露すると卵黄嚢の吸収に伴い, 後期仔魚期に毒性が発現する結果となった.

太陽光照射条件下でのフェニトロチオンの光分解半減期は, 蒸留水中で0.6～1.0日, pH3, 7, 9の緩衝液中ではそれぞれ1.5, 1.0, 0.9日であり, また河川水および海水中では0.9～1.0日であった. フェニトロチオンの蒸留水中における量子収率は8.0×10-4であり, この値を使って計算から求めた北緯40°の秋季における半減期は1.4日と実測値とほぼ一致した. 一方, 土壌薄層プレート上に処理したフェニトロチオンは, おもに揮散や光分解により半減期が約1日の速度で分解・消失した. 水中ではおもに, P=SのP=Oへの酸化, ベンゼン環メチルのカルボン酸への酸化, ニトロ基のアミノ基への還元, カルボン酸とアミノ体が縮合したアミド化合物の生成, P-O-アリルおよびP-O-メチル結合の開裂, 異性化, ベンゾイソキサゾール誘導体の生成, さらにベックマン転位による7員環 (アゼピン誘導体) の生成を経て分解された. 水中での主光分解物はpHにより異なり, 弱酸性および中性ではベンゼン環メチル基がカルボン酸に酸化された分解物 (カルボキシスミチオン) が主であるのに対して, 弱塩基性ではカルボキシスミチオンとそのアミノ体が縮合したアミド化合物が主分解物であった. これらの光分解物はさらに14CO2やフミン酸様物質に分解された. 一方, 土壌表面ではP=SのP=Oへの酸化, P-O-アリル結合の開裂がフェニトロチオンの主光分解反応であった. 通常自然水中において見いだされるpH5～9の範囲でのフェニトロチオンの加水分解半減期は15℃で200～630日, 30℃で17～61日, 45℃で4～8日であった. pH10以上の塩基性条件下ではP-O-アリル結合の開裂物が主分解物であるのに対して, pH8以下ではP-O-メチル結合の開裂物が主分解物であった. 河川水および海水中のフェニトロチオンの光分解および加水分解様式は同じpHを示す緩衝液中とほぼ同じであった.

14C-Fenitrothion at 0.1 ppm in running water, is rapidly absorbed at each stage of the embryo, yolk sac fry, postlarva, juvenile, and adult of the killifish (Oryzias latipes). The14C and fenitrothion concentrations 2 in organisms including those in eggs produced from mature female reach equilibrium after 1 to 3 days exposure except the juvenile stage, which shows a gradual increase in concentration, and the maximum bioaccumulation ratios 3 of the parent compound ranges from 88- (postlarva) to 540-fold (female adult) relative to the water concentration.

プロシミドン (スミレックス®) の緩衝液もしくは自然水中における光分解と加水分解について検討した. プロシミドンの分解は, 太陽光照射条件下においていくらか促進されたものの, おもに加水分解を経て進行した. 本化合物は, pH5以下では水による neutral reaction, pH7～8以上では塩基触媒, pH5～8の範囲では両者の反応を受けて分解した. 自然水において通常見いだされるpH6～9の範囲では, プロシミドンは半減期が0.6日～68日 (15℃), 2時間～18日 (30℃), 0.5時間～8日 (45℃) の速度で加水分解された. また, Arrhenius の式を用いて加水分解速度を温度の関数として表し, 計算から求めた加水分解半減期は実測値とよく一致した. 中性および塩基性条件下では環状イミドの加水分解物が, 一方, 酸性条件下ではさらにアミド結合が開裂した加水分解物が多く検出された.

ベンジルフェニル環およびシクロプロピル環1位を14Cで標識した1R, cis-および1R, trans-サイパーメスリンをキャベツ葉に塗布し, その消長を調べた. 消失半減期は, cis体で7～8日, trans体で4～5日であった. 処理葉から他の部位への14Cの移行はほとんど認められなかった. サイパーメスリンは, cis/transおよび1R/1Sの光異性化, エステル結合の開裂, フェニル環4位もしくはシクロプロピル環2位のメチル基の水酸化, シアノ基のアミド, カルボン酸への加水分解を受けて速やかに代謝され, これらの代謝物はさらに糖と抱合体を形成した.

クロルフェニルおよびベンジルフェニル環を14Cでラベルした脱カルボキシル体を雌雄ラットに4mg/kgの割合で1回経口投与すると, 放射能は速やかに吸収され, 代謝を受けた後におもに糞中に排泄された. 投与1, 3, 6, 9および24時間後に全身オートラジオグラムを撮ると, 放射能はおもに肝臓と胃腸の内容物に存在し, その他の組織への移行はわずかであった. 投与7日目に解剖して22種類の組織を摘出し, 14C組織残留量を調べたところ, いずれも低い値を示した. 脱カルボキシル体は, おもにイソプロピル基の酸化, 3-フェノキシベンジル基の2′, 3′, 4′および6位の環水酸化, シアノ基を有するベンジル位の水酸化を経て代謝された. これらの代謝物は, グルクロン酸抱合体として胆汁中に排泄され, 尿中へはほとんど排泄されなかった. グルクロン酸抱合体は腸肝循環をくり返している間に, 腸内細菌で加水分解されたアグリコンが糞中に排泄されることが明らかになった. 脱カルボキシル体の代謝様式や組織残留量に雌雄および標識位置による顕著な差異は認められなかった.

The metabolism of 3-phenoxybenzoic acid, a common plant metabolite of deltamethrin, cypermethrin and fenvalerate, has been studied in abscised leaves of cabbage, cotton, cucumber, kidney bean and tomato plants. The [14C]-acid was readily converted into more polar conjugates by esterification with glucose, 6-O-malonylglucose, gentiobiose, cellobiose, glucosylxylose and two types of triglucose with different isomerism. Other metabolites identified were the glucosyl ether of 3-(4-hydroxyphenoxy)benzoic acid, and a 3-(2-hydroxyphenoxy)benzoic acid derivative with a total of two molar equivalents of glucose linked to the carboxyl and phenolic -OH groups. The conjugation pathways were somewhat plant-specific. The glucosylxylose ester was found only in cotton, and the cellobiose and triglucose esters were found only in tomato. All of the conjugates except the glucose and glucosylxylose esters were plant metabolites that had not been identified previously. Furthermore, this is the first report to show the presence of cellobiose and triglucose conjugates in plants. However, neither of the acetyl derivatives of the [14C]-triglucoside was identical with the synthetic deca-acetyl derivative of [16]-triglucoside.