阿特拉津及其代谢物在大鼠尿液中的排泄动力学研究

目的:建立大鼠尿液中阿特拉津(ATR)及其代谢物脱乙基阿特拉津(DEA)、脱异丙基阿特拉津(DIA)及脱乙基脱异丙基阿特拉津(DEDIA)的分析方法,并考察其排泄特征。方法:采用乙腈沉淀蛋白、SFC柱富集等对尿液样品预处理;以高效液相色谱法测定大鼠尿液中ATR及其代谢物的含量,色谱柱为WelchromTM C18,流动相为0.5%冰醋酸甲醇液-0.5%冰醋酸水溶液梯度洗脱,检测波长为225nm;大鼠按25、50、125mg·kg-1灌服给予ATR溶液,于给药前和给药后6、12、18、24、48、72h收集尿液测定并计算其72h累积排泄量占给药量比。结果:ATR、DEA、DIA、DEDIA检测浓度线性范围分别为0.5～50、1～100、1～100、15～1500μg·mL-(1r=0.994～0.998),各样本高、中、低浓度的回收率为96.76%～99.03%,日内、日间RSD均<5%;大鼠灌服ATR后,尿样中主要以代谢物DEDIA为主(>75%),而原型、DEA和DIA排泄量均较少(<10%)。结论:所建立的分析方法准确、灵敏、重复性好,适用于尿液中ATR及其代谢物的分析;ATR在大鼠体内以代谢物DEDIA排泄占绝对优势,降解更趋完全。     

The Urinary Excretion of Tryptophan and Tryptophan Metabolites in the Chronic Ethanol-fed Rat

Abstract— An investigation was made into the hypothesis that chronic ethanol ingestion disturbs the metabolism of tryptophan which is reflected by alterations in the urinary excretion of the metabolites 5-hydroxyindoleacetic acid (5-HIAA), anthranillic acid (AA) and indoleacetic acid (IAA). In particular, we investigated whether experimental chronic alcoholism is associated with a decrease in the tryptophan metabolite ratios as suggested in the literature. Male Wistar rats were chronically fed a nutritionally-complete liquid diet in which ethanol comprised 35% of total calories: controls were pair-fed identical amounts of the same diet in which ethanol was replaced by isocaloric glucose. At 6 weeks, 24 h urine samples were collected for the analysis of tryptophan, 5-HIAA, AA and IAA by HPLC. During ethanol-feeding there were reductions in the daily urinary excretion (i.e. μmol/24 h) of tryptophan (–57%, P = 0·026) and concomitant increases in 5-HIAA excretion (62%, P = 0·057). Expression of data in terms of lean tissue mass (i.e. urinary creatinine) revealed identical conclusions. An analysis was performed on the molar ratios of these urinary analytes. The tryptophan: total metabolite ratio was significantly decreased (by ?53%), but the AA: total metabolite ratio was not significantly altered (P = 0·102). The ratios 5-HIAA/AA and 5-HIAA/IAA were slightly increased, but they did not attain statistical significance (P > 0·351). It was concluded that chronic ethanol feeding is associated with significant changes in the urinary excretion of tryptophan and its related metabolites. Many of the above changes were contrary to previous clinical data and this may be due to dietary and nutritional deficiencies or to alterations in the diurnal pattern of 5-hydroxytryptamine and tryptophan metabolism.     

Excretion of Metabolites in Bile Following the Administration of Primaquine to Rats

Following the administration of primaquine diphosphate (20 mg/kg IP), six metabolites of primaquine were found in the bile of rats. Quantitative HPLC of the metabolites revealed that the sum of the six metabolites excreted in the bile represented a quantitative recovery of the dose of primaquine.     

Synthesis of [35S]aryl sulfonyl chlorides from [35S]elemental sulfur

A new synthetic methodology that captures electrophilic ³⁵S₈ with aryl Grignard reagents or lithiates provides entry to a wide variety of [³⁵S]aryl sulfonyl chlorides upon oxidation and chlorination. Copyright © 2005 John Wiley & Sons, Ltd.     

Effects of Ethanol on Recombinant Rat GABAA Receptors: [35S]t-Butylbicyclophosphorothionate ([35S]TBPS) Binding Study

Abstract: To determine the roles of the alternatively spliced short and long forms of the γ2 subunit in the effect of ethanol on the GABA_A receptor function, picrotoxin-sensitive [³⁵S]t-butylbicyclophosphorothionate ([³⁵S]TBPS) binding was studied in recombinant rat α1β2γ2 and α6β2γ2 receptors expressed in human embryonic kidney 293 cells. Ethanol (10–500 mM) in the absence of added GABA had only minor effects on [³⁵S]TBPS binding irrespective of the γ2 splice variant, its effects being greater in α6β2γ2 than in α1β2γ2 receptors. Ethanol (100 mM) decreased the binding in all four subunit combinations at various concentrations of GABA, again an effect independent of the γ2 variant. The two γ2 variants had different effects on GABA modulation of the binding, with the long γ2 variant decreasing the efficiency of GABA inhibition in α6β2γ2 receptors and enhancing the biphasic GABA stimulation and inhibition in α1β2γ2 receptors. The findings confirm the importance of the α subunits in the allosteric interactions between the convulsant binding site and other effector sites, which can be modified only to a minor extent by the type of the γ2 splice variant.     

Metabolism of 3, 4-Dihydroxyphenylalanine,its Metabolites and Analogues in vivo in the Rat: Urinary Excretion Pattern

1. The metabolism and interrelationships of orally and intraperitoneally administered L-dopa, related amino acids and their metabolites have been studied.

2. Amino acids were decarboxylated. N-Methyldopa formed dopamine but not epinine. D-Dopa was absorbed from the intestine and metabolized by a series of reactions which resulted in greater decarboxylation than was observed after L-dopa. Transamination was a minor pathway.

3. m-Hydroxylated phenylpyruvic acids were poorly reduced, but vanilpyruvic acid was reduced fairly readily. Lactic acids were largely unchanged. Lactic and pyruvic acids formed phenylethylamines and their metabolites. Small amounts of phenylpyruvic acids may be decarboxylated to phenylacetic acids.

4. Glycine conjugates were formed from phenylacetic acids, a partially reversible change. 3,4-Dihydroxyphenylacetic acid was metabolized to homo-vanillic and m-hydroxyphenylacetic acids, especially when given orally. Little 3-hydroxy-4-methoxyphenylacetic acid was oxidized to 3,4-dihydroxyphenyl-acctic acid but some increase in m-hydroxyphenylacetic acid excretion was observed.

5. 2-Phenylethanol analogues were largely converted to the corresponding acids. 3,4-Dihydroxyphenylethanol was partially m-O-methylated before oxidation.

6. β-Phenylethylamine analogues were oxidized mainly to phenylacetic acids, but a variable amount of analogous phenylethanol was also formed, especially from m-tyramine. Dopamine was O-methylated, a process not readily reversible. It was also p-dehydroxylated following oral and intraperitoneal administration but not after oral neomycin; biliary excretion of amines may be involved in this sequence of events. N-Methylated amines were oxidized less readily than the parent amine.

7. Differences in route of administration resulted in quantitative changes in degradation pathways, an effect deriving, to some extent, from p-dehydroxylation and O-methylation in the gut.     

Biliary Excretion of Diazepam and its Metabolites in Man

Abstract: Ten mg diazepam was given intravenously to 12 patients with a T-tube in the common bile duct after choledochotomy (Group I) and to 10 patients after cholecystectomy (Group II). The concentrations of diazepam, of its main metabolite, N-demethyldiazepam, and of free oxazepam in the plasma of both groups and the conjugated and free concentrations of diazepam, N-demethyldiazepam, and oxazepam in the bile in the Group I were measured by gas chromatography. In Group I significantly lower plasma diazepam concentrations were obtained as compared with Group II indicating an enterohepatic circulation of diazepam. There was no significant difference in the concentrations of N-demethyldiazepam in the plasma between the two groups. In Group I the patients had frequently more free oxazepam in their plasma than in Group II. The main conjugated metabolite in the bile was N-demethyldiazepam (about 74 %). Traces of diazepam were in the conjugated form, but no conjugated oxazepam was found in the human bile. The enterohepatic circulation of diazepam and its metabolites may be partly responsible for the prolonged effects of diazepam.     

石榴皮鞣质对大鼠尿液内源性物质代谢的影响

摘 要 目的： 采用代谢组学方法考察石榴皮鞣质对正常大鼠尿液内源性物质代谢的影响。方法: 将大鼠分为空白对照组、石榴皮鞣质给药组,每组按 78.5 mg·ml^-1剂量对大鼠连续灌胃给药4周,收集尿样,用于代谢组学研究。HPLC-MS采集大鼠尿样的数据信息,运用SIMCA-P软件中的PCA 法与PLS DA 法对比分析。结果:石榴皮鞣质给药组与空白对照组得分点达到很好的区分效果, 连续给药22 d 时, 尿液内源性物质代谢改变最为明显。结论: 石榴皮鞣质提取物显著影响大鼠尿样中与药理作用相关内源性物质的代谢, 为深入研究石榴皮鞣质提供依据。     

Excretion of Methyl Mercury in Rat Bile: The Effect of Thioctic Acid,Thionalide, Hexadecyl- and Octadecylmercaptoacetate

Abstract: Thioctic acid markedly increases the sulfhydryl and sulphide content of bile. This probably reflects the reduction of thioctic acid in the liver, followed by biliary excretion of a reduced derivative. The total biliary excretion of methyl mercury was not increased. Thionalide markedly inhibits biliary excretion of methyl mercury. Simultaneously, the sulfhydryl and sulphide content of bile decreases. This is probably caused by the conjugation of thionalide to glutathione in the liver, thereby blocking the biliary excretion of methyl mercury. Hexadecylmercaptoacetate increases the biliary content of methyl mercury moderately after a temporary decrease, whereas biliary sulfhydryl and sulphide concentrations were unchanged. Octadecylmercaptoacetate does not change the biliary content of methyl mercury, sulfhydryl and sulphides significantly. Smaller parts of hexadecylmercaptoacetate, octadecylmercaptoacetate and thionalide seemed to be excreted as such in bile. These results indicate that methyl mercury cannot be transported from liver to bile as complexed to the sulphides thioctic acid, thionalide, hexa- and octadecylmercaptoacetate.     

Impulse-response Studies on Tracer Doses of [14C]Lignocaine and its Multiple Metabolites in the Perfused Rat Liver

The outflow-concentration-time profiles for lignocaine (lidocaine) and its metabolites have been measured after bolus impulse administration of [¹⁴C]lignocaine into the perfused rat liver. Livers from female Sprague-Dawley rats were perfused in a once-through fashion with red-blood-cell-free Krebs-Henseleit buffer containing 0 or 2% bovine serum albumin. Perfusate flow rates of 20 and 30 mL min^? were used and both normal and retrograde flow directions were employed. Significant amounts of metabolite were detected in the effluent perfusate soon after lignocaine injection. The early appearance of metabolite contributed to bimodal outflow profiles observed for total ¹⁴C radioactivity. The lignocaine outflow profiles were well characterized by the two-compartment dispersion model, with efflux rate «influx rate. The profiles for lignocaine metabolites were also characterized in terms of a simplified two-compartment dispersion model. Lignocaine was found to be extensively metabolized under the experimental conditions with the hepatic availability ranging between 0.09 and 0.18. Generally lignocaine and metabolite availability showed no significant change with alterations in perfusate flow rate from 20 to 30 mL min^? or protein content from 0 to 2%. A significant increase in lignocaine availability occurred when 1200 μm unlabelled lignocaine was added to the perfusate. Solute mean transit times generally decreased with increasing flow rate and with increasing perfusate protein content. The results confirm that lignocaine pharmacokinetics in the liver closely follow the predictions of the well-stirred model. The increase in lignocaine availability when 1200 μm unlabelled lignocaine was added to the perfusate is consistent with saturation of the hydroxylation metabolic pathways of lignocaine metabolism.     

Metabolism of Papaverine I. Identification of Metabolites in Rat Bile

1. After hydrolysis with glusulase of bile from rats treated with papaverine, four metabolites (A, B, C and D) were separated.

2. The structures of A, B and C were established as the monodemethylated compounds, 4′-desmethyl-, 7-desmethyl-, and 6-desmethylpapaverine, respectively.

3. D was formed from papaverine by bis-demethylation. Since it was found in cat bile after administering either A or C, but not B, it was identified as 4′,6-desmethylpapaverine.     

罗布麻叶对大鼠尿液内源性物质代谢的影响

目的：采用代谢组学方法考察罗布麻叶对正常大鼠尿液内源性物质代谢的影响。方法：罗布麻叶用10倍量70%乙醇回流提取,将大鼠分为空白对照组、罗布麻叶高剂量组及低剂量3组,连续灌胃给药29 d,运用SIMCA-P软件中的PCA法与PLS-DA法对比分析。结果：罗布麻叶给药组与空白对照组得分点达到很好的区分效果,连续给药22 d时,尿液内源性物质代谢改变最为明显。相比于罗布麻叶低剂量组,高剂量组与空白对照组之间差距更大。结论：罗布麻叶提取物对正常大鼠机体内源性物质代谢产生了影响,为进一步阐释罗布麻叶的药性研究工作提供了依据。     

静脉注射蟾毒它灵和华蟾毒它灵后大鼠胆汁中代谢产物的UPLC-UV-MS法分析

建立了超高效液相色谱-紫外分光光度-质谱(UPLC-UV-MS)法研究蟾毒它灵和华蟾毒它灵静脉给药后大鼠胆汁中的代谢产物.UPLC的高分辨率能够基线分离胆汁中的原药和代谢物,UV光谱图揭示了各种化合物量的关系,MS进一步对代谢物进行结构表征.结果显示,大鼠胆汁中原药的含量小于5%,主要代谢物是去乙酰基并羟基化蟾毒它灵和去乙酰基华蟾毒它灵.表明蟾毒它灵在大鼠体内代谢途径主要是水解并羟基化,华蟾毒它灵主要是水解反应.     

Chlorprothixene and its Metabolites in Blood,Liver and Urine from Fatal Poisoning

Abstract: A spectrophotometric method for the quantitative determination of chlorprothixene (CPT) and its metabolites in autopsy material has been developed. The method involves repeated extractions with non-polar solvents at pH 11–12 and thin-layer chromatographic separation, followed by u.v. spectrophotometry of hydrochloric acid-methanol extracts of the chromatographic fractions. The method which has a lower detection limit of 0.1 μ/g material, was used for blood, urine and liver from 12 cases, in which CPT was considered as the only or contributory cause of death. In the cases in which death occurred due to CPT only (2.5–4 g of CPT orally), the total concentration of thioxanthenes (i.e. CPT and its metabolites) were 0–1 μg/mg in the blood, 0.1–15 μg/ml in the urine and 22–86 μg/g in the liver. This indicates an extremely uneven distribution of thioxanthenes in the body. In addition to unchanged CPT, 5 thioxanthene metabolites were detected in the material. Three metabolites were identified as chlorprothixen-sulphoxide, N-monodemethylchlorprothixene and N-monodemethylchlorprothix-cnsulphoxide, respectively. The two unidentified thioxanthenes on the basis of their u. v. absorption spectra were assumed to be a sulphoxide and a non-sulphoxide metabolite of CPT. It is concluded that CPT is a more toxic drug than previously believed, and that the total concentration of thioxanthenes in the liver is the most suitable parameter for the toxicological evaluation of fatal CPT poisonings.     

Synthesis of acyl[35S]sulfonamides: Coupling of high specific activity [35S]methane sulfonamide with acids and acid chlorides

Direct coupling of high specific activity [³⁵S]methanesulfonamide, generated from [³⁵S]methanesulfonyl chloride and ammonia, with acids and acid chlorides afforded the corresponding [³⁵S]acyl sulfonamides in excellent yields. Examples of high specific activity [³⁵S]acyl sulfonamides were prepared containing functionality that can be further elaborated through carbon–carbon or carbon–nitrogen bond forming reactions.     

Excretion of Zinc in Rat Bile – A Role of Glutathione

Abstract: Fractionation of the bile from rats injected with ⁶⁵ZnCl₂ (5 μmol/kg) showed that zinc was mainly bound to low molecular weight compounds eluted corresponding to the zinc-glutathione complexes. Diethylmaleate (3.9 mmol/kg), cyclohexene oxide (4.9 mmol/kg) and acrylamide (3.5 mmol/kg) administered intraperitoneally to rats caused a rapid decrease in the endogenous excretion of both zinc and reduced glutathione into bile. This depression probably reflects the conjugation of the aforementioned substances to glutathione in the liver cells. These results indicate that zinc is transferred from liver to bile by glutathione dependent process and most likely as zinc-glutathione complexes.     

Characterization of [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding to GABAA receptors in postmortem human brain

BACKGROUND AND PURPOSE: The aim of the present study was to determine whether binding of [(35)S]t-butylbicyclophosphorothionate ([(35)S]TBPS) to the convulsant binding site of GABA(A) receptors in human postmortem brain samples can be used as an in vitro index of the functional activation of these receptors. EXPERIMENTAL APPROACH: Postmortem stability of [(35)S]TBPS binding was assessed in rat brain samples harvested at various times after death and the binding properties of [(35)S]TBPS binding (K(D) and B(max)) were determined in human postmortem brain using radioligand binding studies. In addition, the ability of human brain [(35)S]TBPS binding to be allosterically modulated by compounds that bind at recognition sites distinct from the convulsant binding site was measured. KEY RESULTS: Whereas binding of [(3)H]Ro 15-1788 to the benzodiazepine binding site and [(3)H]muscimol to the agonist (GABA) binding site were retained over a 20 h postmortem interval, there was a significant decrease in the affinity and number of [(35)S]TBPS binding sites. Nevertheless, [(35)S]TBPS binding in human brain could be inhibited by TBPS, picrotoxin, loreclezole and pentobarbital and modulated by GABA with potencies comparable to those observed in rats. In addition, the GABA-induced reduction in human brain [(35)S]TBPS binding could be modulated by benzodiazepine site ligands in a manner that reflected their intrinsic efficacies. CONCLUSIONS AND IMPLICATIONS: These results suggest that allosteric coupling between the [(35)S]TBPS, GABA and benzodiazepine binding sites is preserved in postmortem human brain and that [(35)S]TBPS binding in this tissue may be used to study functional characteristics of native human GABA(A) receptors.     

The uptake of [35S]methimazole by sheep thyroid slices in vitro

The uptake of [³⁵S]methimazole by sheep thyroid slices has been shown to be activated in the presence of iodide. The total uptake (Q) of [³⁵S]methimazole was shown to be the sum of a saturable process and a non-saturable process. The constants Q_max, K_s and P in the two-term equation were determined using a published statistical method and a Fortran IV computer programme. Diiodotyrosine (DIT) at a 0.1 mM concentration stimulated the saturable uptake of [³⁵S]methimazole appreciably in the absence of iodide, whilst thyroid-stimulating hormone (TSH) inhibited uptake in the presence of iodide and was of no effect in the absence of iodide. Propylthiouracil (PTU) inhibited the saturable uptake of [³⁵S]methimazole whilst perchlorate had no effect.