[4-¹⁴C] testosterone was incubated with liver homogenates of normal or carbon tetrachloride (CCl₄) injured male rats in the presence of NAD at 37°C for 90min. The metabolites produced were identified by thin layer chromatography and chemical transformation.
In the normal liver homogenates, 5a-androstane-3a, 17β-diol, epiandrosterone and 16α-hydroxy testosterone were the predominant metabolites amounting to as much as 72% of the total metabolites.
In the injured liver homogenates, an unmetabolized substrate was detected in a large amount. Δ⁴-androstene-3, 17-dione, 5a-androstane-3, 17-dione and androsterone were present in larger amounts, while the amount of their end product, 5α-androstane-3α, 17β-diol, was less than that in the normal. 16α-, 7α-and 6β-hydroxy testosterones were in smaller amounts compared with those in the normal.
These findings suggest that the hydroxylation of testosterone and the reduction of the 17-ketone to a 17-hydroxyl, i.e., the conversion of androsterone to 5α-androstane-3αa, 17β-diol, might be impaired by the administration of CCl⁴.

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Castration in male rats decreased the activities of testosterone and progesterone hydroxylations and reduced the magnitude of spectral change caused by testosterone and progesterone in liver microsomes, accompanying less marked decrease in microsomal P-450 content and NADPH-neotetrazolium reductase activities. The administration of testosterone or methyltestosterone to the castrated rats completely restored the hydroxylating activities and magnitude of the spectral change. The simultaneous injection of estradiol or diethylstilbestrol blocked the action of the androgens. These results suggest that androgen increases the binding capacity of P-450 with steroid hormones and makes an increase in the hydroxylating activities and that estrogen directly prevents the above action of androgen.

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Intraperitoneal administration of 250mg/kg of PCB (Aroclor 1248) to carp stimulated the metabolism of progesterone, estradiol-17β and testosterone by hepatopancreatic microsomes: the activity of progesterone hydroxylase was increased by 148% in the PCB-treated group, while those of estradiol-17β and testosterone hydroxylases were elevated by 30% and 108%, respectively. A significant reduction in plasma sex hormone levels was also observed in the fish treated with PCB: the plasma concentrations of progesterone and estradiol-17β in female carp were lowered by 56% and 26%, respectively, while that of testosterone in male carp was reduced by 53%. This reduc-tion in circulating sex hormones is probably attributable to elevated metabolism of sex hormones in the hepatopancreas. The ability of PCB to alter the plasma levels of sex hormones raises the possibility that PCB accumulated in fish at high concentrations colud have a deleterious effect on fish reproduction.

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Adrenalectomy in male rats slightly decreased cytochrome P-450 content in liver microsomes. The magnitude of testosterone-induced spectral change and the hydroxylating activity for testosterone by liver microsomes were markedly decreased to a similar extent in adrenalectomized male rats. Similar results were obtained, when progesterone was used as the substrate. The magnitude of testosterone-or progesteroneinduced spectral change per unit of P-450 was also decreased in the adrenalectomized males. These results suggest that the binding capacity of cytochrome P-450 for testosterone or progesterone was decreased after adrenalectomy.
In contrast to the results obtained with male rats, the binding capacity of cytochrome P-450 and the hydroxylating activity for testosterone or progesterone were not significantly decreased in the adrenalectomized females. Similarly, the binding capacity of P-450 and the hydroxylating activity for testosterone or progesterone were not significantly decreased by adrenalectomy in castrated male rats and male and female mice. However, adrenalectomy in castrated and testosterone-treated male rats produced the effects similar to those observed in the intact male rats.
These results indicate that the action of androgen to increase the binding capacity of cytochrome P-450 for steroid hormone was impaired in the adrenalectomized rats and consequently the hydroxylating activity for steroid hormones by liver microsomes was decreased.

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4-¹⁴C-testosterone was incubated with hepatic microsomal and soluble fractions of normal, CCl₄ and ethionine administered male rats in the presence of NADPH at 37° for 90minutes. The metabolites produced were detected by thin layer autoradiography and chemical transformation.
In the microsomal metabolism by the CCl4-injured liver, a high amount of the unmetabolized substrate remained and hydroxytestosterones were remarkably lower than those by the normal liver. These findings indicate that hydroxylation of testosterone is impaired by the administration of CCl₄. In the soluble fraction, most of the substrate was not metabolized by the CCl₄₊Injured liver and little hydroxytestosterone was found. The amount of 5β-androstane-3β, 17β-diol, which was the predominant metabolite by the normal liver, was significantly reduced. These findings indicate the impairment of Δ⁴-5β-hydrogenase.
In the microsomal metabolism by the ethionine-injured liver, the amount of the unmetabolized substrate was less than that in the microsomal metabolism by the CCl₄-injured liver, but the hydroxylation of testosterone was not significantly suppressed. In the metabolism by the soluble fraction, a slightly higher amount of the unmetabolized substrate was found, but no impairment of Δ⁴-5β-hydrogenase was observed.

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Condeinone (1) was oxidized to codeinone 7, 8-oxide (2) by hydrogen peroxide. Stereospecific reduction of 2 by sodium borohydride afforded codeine 7, 8-oxide (3). The configuration of 3 was confirmed by X-ray analysis.

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Progesterone hydroxylation activity of liver microsomes was investigated in male and female rats under altered states of thyroid function. Treatment with thyroxine markedly decreased the activity of progesterone hydroxylation by liver microsomes in male rats, but did not significantly alter the activity in female rats. In contrast, the conversion of progesterone to Δ⁴-reduced metabolites was increased by treatment of male rats with thyroxine. Thyroidectomy also markedly decreased the progesterone hydroxylating activity in male rats, but did not decrease in female rats. The content of P-450 per microsomal protein and the magnitude of progesterone-induced spectral change per microsomal protein and per P-450 were decreased in thyroxine-treated male rats, but similar changes were not observed in thyroidectomized male rats.
From these results it is conceivale that the progesterone hydroxylating activity may be reduced through the decrease in the content of P-450 and the substrate in-teraction with P-450 in liver microsomes from thyroxine-treated male rats, whereas in those from thyroidectomized rats, the hydroxylating activity may be reduced through the decrease in the reduction of P-450 binding to the substrate.
These results indicated that the effects of thyroxine treatment and thyroidectomy on the progesterone hydroxylating activity in liver microsomes of male and female rats were similar to those on the activities of aminopyrine N-demethylation and hexobarbital hydroxylation which are regulated by androgen. On the basis of these results, mechanism(s) of decrease in the progesterone hydroxylating activity in thyroxine-treated and thyroidectomized male rats is discussed.

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It was reported that there was a remarkable difference in the effects of pentobarbital (1) or hexobarbital (2) between adult female and male rats and that there was a sex difference in the metabolism of these drugs (1, 2). However, most works on the effects of barbiturates had been done with either male or female animals only. Moreover, the reports on the sex difference of the effects of barbiturates were principally concerned with the single injection of drug.
The authors have reported that the sex difference was observed in the effects of some hormones on the growth and development of rats and the enzyme activity in the rat's liver (3-5).
The purpose of the present -study was to compare the effects in male and female rats of continued daily injection of pentobarbital as well as phenobarbital. The development of the tolerance to drugs and the existence of sex difference in drug effects were observed.

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The presence of octopamine in the secretion of the salivary gland of Octopus vulgaris was first demonstrated by Erspamer (1). Kakimoto and Armstrong (2) showed the occurrence of this amine in various tissues of rabbits treated with monoamine oxidase inhibitors. However, paper chromatographic studies of the tissue level of octopamine did not give precise information about small changes of the amine level. Based upon the reaction that octopamine is converted quantitatively to p-hydroxybenzaldehyde by periodate oxidation in ammonia alkaline medium (3), the amount of tissue and blood octopamine could be evaluated by measuring the ultraviolet absorption of the oxidation product. In the present experiments the distribution of exogenously administered octopamine and the accumulation of endogenous octopamine after a monoamine oxidase inhibitor were studied in the blood, brain stem, heart, submaxillary glands, spleen and stomach of the rat.

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The activity of drug-metabolizing enzymes of liver microsomes is inhibited by various compounds and the administration of these compounds markedly alters the pharmacological activities of other drugs (1-3).
Iproniazid is a well-known inhibitor of monoamine oxidase and it was the first compound of hydrazine derivatives as the inhibitor of drug metabolizing enzymes (4). Moreover, the other monoamine oxidase inhibitors, such as JB 516 (phenylisopropylhydrazine) and W 1544 (phenethylhydrazine) inhibited the metabolism of hexobarbital and meprobamate (5-7). La Roche and Brodie (6) showed that the activity of these compounds as the inhibitor of hexobarbital metabolism is not related to their ability to inhibit monoamine oxidase.
On the other hand, it has been established that the compounds of low lipid solubility are not metabolized by liver microsomes (8). It is, therefore, likely that the lipid solubility of hydrazine derivative may be an important factor for the inhibition of drug-metabolizing enzymes.
In the present communication, we wish to report that isoniazid and many other hydrazine derivatives inhibit the oxidation of hexobarbital, pentobarbital, meprobamate and carisoprodol and the N-demethylation of aminopyrine both in vitro and in vivo in relation to their lipid solubility.
These results are typical example to show that the lipid solubility of compounds is more important factors rather than their chemical configuration for the inhibition of drugmetabolizing enzymes of liver microsomes.

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1. Predonisolone and hydrocortisone competitively inhibited aniline hydroxylation and aminopyrine demethylation activities.
2. Addition of predonisolone or hydrocortisone to liver microsomes caused the appearance of a difference spectrum similar to that caused by aniline.
3. These steroid hormones not only inhibited the appearance of the aniline difference spectrum but also changed the shape of the spectrum.
4. The activity of aniline hydroxylation may be due to the simultaneous action of two or more enzymes, as suggested by the results on enzyme activities and difference spectra.
5. These results demonstrated that steroid hormones, like drugs, interact with the microsomal electron transport system, and the activities of the drug-metabolizing enzyme were closely related to the metabolism of steroid hormones.

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合成steroidの代謝は一般に肝での水酸化により特徴づけられる. 本実験では, 17α-ethynyl-estrenol (EEL)を例としてとりあげ, このsteroidの代謝に水酸化反応が関与する可能性と, その特徴を主としてウサギ肝とのincubation実験で検討し以下の結果を得た. すなわちEELの代謝は3位の水酸化にはじまる. そしてこの反応には分子状酸素, NADPH₂が必要で肝ミクロソーム分画に酵素活性が高い. 次にいわゆる薬物代謝酵素による水酸化と比較する目的でmethylhexobarbitalの水酸化を同時に検討したが, その結果両者の水酸化酵素活性はいくつかの点で相異し, EELの水酸化にはcyt. P-450以外にさらに他の因子が介在し, それがEEL水酸化の律速段階となりうる可能性が示された.

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The metabolic fate of a new analgesic agent, 1-n-butyryl-4-cinnamylpiperazine hydrochloride (BCP-HCl) in the rat was investigated in vivo and in vitro.
The following four urinary metabolites were detected in addition to the unchanged drug by both the thin-layer (TLC) and gas-liquid chromatography (GLC); 1-n-butyrylpiperazine (I), 1-n-butyry1-4-(4'-hydroxycinnamyl) piperazine (III), 1-(4'-hydroxycinnamyl)-piperazine (IV) and 1-cinnamylpiperazine (V). These were isolated and identified physicochemically (ultraviolet, infrared and mass spectrometry and mixed melting point test). In addition to the above metabolites, piperazine hexahydrate (II) and two unidentified products, UK-1 and UK-2 were detected in the urine by the TLC but not by the GLC.
In the bile BCP, I, III, and IV were detected in addition to the glucuronide and sulfate conjugates of III and IV. One unknown metabolite corresponding to the urinary UK-1 was also detected by the TLC of the biliary metabolites hydrolyzed with β-glucuronidase or arylsulfatase.
In vitro incubation of BCP-HCl with the post-mitochondrial fraction of the rat liver resulted in the formation of the four metabolites, I, III, IV and V.

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Plasma levels of trimetazidine in rabbits, rats, and mice were determined. Plasma levels in animals showed unusual curve about 1 hr after oral administration and this reason was investigated by determining distribution of the drug in animal tissues and excretion of the drug in bile.
Metabolic pathways of trimetazidine in rabbits were investigated qualitatively and it was ascertained by thin-layer chromatography that the methylene group connecting the benzene and piperazine rings is not severed by metabolism in rabbits.

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A simple assay method for testosterone hydroxylase activity by thin-layer chromatographyultraviolet spectrophotometry was developed. By using this method, the effects of various H₂-receptor antagonists (cimetidine, CIM ; metiamide, MET ; ranitidine, RAN ; famotidine, FAM) or imidazole (IMZ) on the hydroxylations of testosterone by mouse liver microsomal enzymes were studied in vitro. CIM and MET inhibited the 6β-, 7α-and 16α-hydroxylations in a dose-dependent manner. RAN and FAM had little inhibitory effect on any hydroxylation. IMZ inhibited the 6β-hydroxylation to the same degree as CIM and MET, while the effects on the 7α-and 16α-hydroxylations were very weak. The kinetic data indicated that these drugs inhibited the three hydroxylation reactions competitively and the affinities for each hydroxylase varied from drug to drug. The results suggest that the inhibitory actions of CIM or MET on the hydroxylations of testosterone are due to the imidazole ring structure, and the side chain structures may play a role in the enhancement of affinity to the enzymes, particularly the 7α-and 16α-hydroxylases. On the other hand, RAN and FAM containing a ring structure different from imidazole had little effect on any testosterone hydroxylase.

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The N-demethylation of five antihistaminics possessing diemethylaminoalkyl group was compared in in vitro production of formaldehyde by liver 9000 g supernatant fraction from four animal species, rat, mouse, guinea pig and rabbit. Sex difference was observed in only rats but the demethylating activities varied from species to species for a drug and from drug to drug in a species. The high demethylating activities were shown for trimeprazine or diphenhydramine by rats and for fenethazine or chlorpheniramine by rabbits. In adult male rats, castration or SKF 525A reduced the activities and 19-nortestosterone phenylpropionate enhanced the activities without the big change in relative order. Phenobarbital induced the activities of female rat liver in almost same proportion for every drug but 3-methylcholanthrene did not show stimulatory effect. The formaldehyde production from N-oxides was comparatively small and did not show the difference among drugs. No correlation between the lipid solubility and the N-demethylation was found. The significance of investigation of species differences in the drug metabolism was discussed.

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In order to examine the occurrence of "NIH shift"during hydroxylation of the aromatic steroid, 2-and 3-deuterio-3-deoxyestrones (IIIb, V) were synthesized as substrate. After oral administration of these labeled steroids to a rabbit, two principal metabolites, 2-hydroxy-3-deoxyestrone (Ib) and 17α-estradiol, were isolated from the collected urine specimen. Inspection of mass and nuclear magnetic resonance spectra revealed that aryl hydroxylation was accompanied by a migration of deuterium from the initially labeled site to an adjacent position. The direction and extent of isotope migration are listed in Table I.

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