Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Enzymic azoreduction of the hepatocarcinogen, N,N-dimethyl-4-aminoazobenzene (DAB) and glucuronidation of its ring-hydroxylation product, 4'-hydroxy-DAB, by hepatic microsomal fractions in vitro were studied during an eight day period of hepatic regeneration following partial hepatectomy in Wistar rats. Azoreduction of DAB and its N-demethylated metabolites did not significantly change during hepatic regeneration in contrast to N-demethylation of these dyes which is profoundly suppressed during regeneration. UDP-Glucuronosyltransferase (UDP-GT) activity towards 4'-hydroxy-DAB was partially depressed during the regeneration period, but the depression was considerably less than that for bilirubin. Transferase activity towards 4-nitrophenol, after initial depression, returned to normal levels after the third day of partial hepatectomy. 2. In Gunn rats, microsomal UDP-GT activity towards bilirubin was undetectable, whereas transferase activity toward 4-nitrophenol was 50% of normal. Addition of diethylnitrosamine (DEN) in vitro restored transferase activity towards 4-nitrophenol to normal levels, but the activity towards bilirubin was unaffected. Gunn rat UDP-GT activity towards 4'-hydroxy-DAB was 25% of normal and was partially activated upon addition of DEN in vitro. 3. Treatment with clofibrate of beta-naphthoflavone induced hepatic microsomal bilirubin- and 4-nitrophenol-specific UDP-GT activities, respectively; both agents induced transferase activity towards 4'-hydroxy-DAB. Triiodothyronine, which induces 4'-nitrophenol-specific UDP-GT and depresses bilirubin-specific UDPG, had little effect on 4'-hydroxy-DAB UDP-GT activity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Microsomal azoreduction and glucuronidation in the metabolism of dimethylaminoazobenzene by the rat liver. 311 67

The potentials of octachlorostyrene (OCS) and hexachlorobenzene (HCB) to induce liver microsomal ethoxyphenoxazone deethylation (an indicator of induction of 3-methylcholanthrene and beta-naphthoflavone-like cytochrome P-450 monoxygenase activity) and cause porphyria in male C57BL/6 and C57BL/10 mice and female F344 rats were compared. Ethoxyphenoxazone deethylation was induced much more by HCB than by OCS in both of these strains of mice (although neither OCS nor HCB greatly induced deethylation in the DBA/2 strain). In rats ethoxyphenoxazone deethylase was induced 26-fold by HCB but only four-fold by OCS, whereas dealkylation of pentoxyphenoxazone (an indicator of phenobarbital-like induction) increased 43- and 36-fold, respectively. Both chemicals were poor inducers of dealkylation of pentoxyphenoxazone in mice. When fed HCB continuously but not when given OCS, C57BL/6 and C57BL/10 mice (both after pretreatment with iron) and F344 rats developed porphyria with a depression of hepatic uroporphyrinogen decarboxylase activity. The results illustrate that in these species OCS and HCB cannot be considered as equally efficient agents for inducing ethoxyphenoxazone deethylation or causing porphyria. If these effects are mediated through binding to the aromatic hydrocarbon responsiveness (Ah) receptor, HCB would appear to have a much greater affinity than OCS despite the face that neither chemical possesses a structure currently considered to be necessary for efficient binding.
 ...
PMID:Distinction between octachlorostyrene and hexachlorobenzene in their potentials to induce ethoxyphenoxazone deethylase and cause porphyria in rats and mice. 327 68

The subchronic dermal toxicity of a medium-boiling coal liquefaction product (CLP, 154-378 degrees C) was investigated in the rat. CLP was applied to the shaved backs of rats at dose levels of 50, 100, 200, or 400 mg/kg body weight.d, 7 d/wk for a period of 13 wk. Control groups received 0.4 ml/kg of normal saline. Signs of dermal irritation were observed at sites of application in males dosed at 200 and 400 mg/kg body weight and were characterized by thickened, focally necrotic and ulcerative skin. All animals survived the full length of the treatment period. Growth depression was observed in males at all dose levels, but no significant decrease in weight gain was observed in females. An increase in liver/body weight ratios was observed in all treatment groups of both sexes. The organ/body weight ratios for the spleen, heart, kidney, and brain were also increased in the upper dose groups of both sexes. Treatment with CLP caused a dose-dependent decrease in hemoglobin and packed cell volume in both sexes of all dose groups. The number of erythrocytes was decreased and that of neutrophils was increased in some CLP-treated groups of both sexes. There was a mild myeloid hyperplasia with increased myeloid/erythroid ratios in the 200- and 400-mg/kg groups of both sexes. Hepatic microsomal ethoxyresorufin deethylase activity was increased in all treatment groups of females, and in males dosed at 100 mg/kg and higher. In the renal tubules mild treatment-related histological changes occurred, which consisted of eosinophilic inclusions, increased cytoplasmic volume, and pyknosis. These changes were noted in the high-dose groups of both sexes. These data indicate that the medium-boiling CLP could produce systemic toxicity when applied dermally at 50 mg/kg body weight.d.
 ...
PMID:Dermal toxicity of a medium-boiling (154-378 degrees C) coal liquefaction product in the rat--Part I. 334 96

The study of the influence of the age of the animals (13 to 53 weeks) on the rate of ethanol metabolism in vivo and the total activity of liver alcohol dehydrogenase and microsomal ethanol oxidizing system showed a progressive decline with age. These effects were observed concomitantly with a diminution in the content of cytochrome P-450 and microsomal functions related to oxidative and free-radical mediated reactions, namely, NADPH oxidase activity, NADPH-dependent oxygen uptake and NADPH-or t-butyl hydroperoxide-induced chemiluminescence. It is concluded that ageing is accompanied by a diminution in the total oxidative activity of the liver tissue, which would explain the depression in basal and ethanol-induced lipid peroxidation found in the oldest group of rats studied.
 ...
PMID:Age-dependent changes in in vivo ethanol metabolism and in the activity of hepatic enzymes involved in ethanol oxidation and microsomal functions. 334 70

If given orally captan is relatively nontoxic, but it can be extremely toxic after parenteral exposure. Therefore, a single i.p. dose of captan (20 mg/kg) was given to male Sprague-Dawley rats and its effect on liver microsomal mixed function oxidases and certain serum enzymes (SDH, SGPT and SGOT) was studied. The single dose of captan caused marked depression of microsomal cytochrome P-450 and the activity of benzphetamine N-demethylase and aniline hydroxylase, and moderate elevation of the serum enzymes indicative of liver damage. However, reduced glutathione (100 mg/kg, i.p.) given prior to captan, appears to decrease the liver toxicity as measured by reduced inhibition of the microsomal enzymes and elevation of serum enzymes activity. The results suggest that glutathione and other compounds containing sulfhydryl groups may protect the subjects from captan-induced liver toxicity.
 ...
PMID:Involvement of glutathione in the reduction of captan-induced in vivo inhibition of monooxygenases and liver toxicity in the rat. 338 36

The participation of the microsomal ethanol oxidizing system (MEOS) and catalase in total ethanol metabolism is reviewed. Non-alcohol dehydrogenase (ADH) dependent pathways contribute to in vivo ethanol metabolism, but the respective role of each has long been debated. The principal data supporting a role for catalase is an occasionally reported moderate depression of ethanol metabolism after aminotriazole. In deermice lacking ADH, we observed a slight (though not statistically significant) decrease in basal ethanol metabolism of hepatocytes after aminotriazole. However, this decrease was found to parallel a similar inhibition of MEOS by aminotriazole, and thus may not reflect catalase mediated peroxidation in this animal. 1-butanol, a competitive inhibitor of ethanol oxidation by MEOS and not a substrate for catalase, decreased ethanol metabolism by hepatocytes in a concentration dependent manner. These results, as well as those from other investigators, indicate that MEOS mediates virtually all of non-ADH ethanol metabolism in vivo.
 ...
PMID:Ethanol metabolism in alcohol dehydrogenase deficient deermice is mediated by the microsomal ethanol oxidizing system, not by catalase. 342 85

Repeated administration of human chorionic gonadotropin to rats results in a maximal depression of testicular microsomal heme and cytochrome P-450 levels at 24 h, followed by increases that plateau at pretreatment levels by day six. Associated with the depressed levels of microsomal heme and cytochrome P-450 is an increase of testicular microsomal heme oxygenase activity at 12-24 h. Testicular mitochondrial delta-aminolevulinic acid synthase activity was increased at 24 h, and remained elevated throughout the 9-day treatment period. Pretreatment with 1,4,6-androstatrien-3,17-dione, an aromatase inhibitor, failed to prevent the depression of testicular microsomal heme or cytochrome P-450 or increased heme oxygenase activity caused by repeated administration of human chorionic gonadotropin, and administration of estradiol benzoate failed to alter testicular microsomal heme oxygenase activity suggesting that these parameters were not related to altered testicular estrogen content caused by increased aromatase activity. These results suggest that increased testicular heme oxygenase activity is associated with decreased microsomal heme and cytochrome P-450 content during human chorionic gonadotropin-induced desensitization.
 ...
PMID:Increased rat testicular heme oxygenase activity associated with depressed microsomal heme and cytochrome P-450 levels after repeated administration of human chorionic gonadotropin. 348 41

To explore which rat liver cytochrome P-450 species are involved in aldrin epoxidation, we have studied the catalytic activities of a series of cytochrome P-450 isozymes purified from untreated and inducer-treated Sprague-Dawley rats. Of ten cytochrome P-450 forms analyzed, seven isozymes, listed in order of decreasing activity, catalyzed aldrin epoxidation: P-450UT-A, P-450PB-C, P-450UT-H, P-450PB-B, P-450PCN-E, P-450UT-F, and P-450PB-D. P-450UT-I, P-450BNF-B, and P-450ISF-G were not very active at all. A novel aldrin metabolite, endo-dieldrin, was formed by cytochrome P-450UT-F in a 6-fold excess over dieldrin, which is the exo-isomer. The activity of aldrin epoxidase furthermore was assayed in liver microsomes from Sprague-Dawley rats of diverse physiological status and after pretreatment with various inducers resulting in a peculiar pattern of cytochrome P-450 isozymes. Untreated animals, at an age of 3 weeks, showed similar enzyme activities in both genders. During maturation, the activity of males increased by 3-fold, while the activity in females did not significantly change during this period. Pretreatment with pregnenolone-16-alpha-carbonitrile or dexamethasone strongly increased the activity in females. Pretreatment with dexamethasone did not increase the activity of males. A 50% depression of epoxidase activity was noted for males pretreated with 5,6-benzoflavone. Phenobarbital pretreatment increased the activity of females by 12-fold and of males by 2-fold. Males responded to pretreatment with polychlorinated biphenyls in a strain dependent fashion: enzyme activity was increased 2-fold in Sprague-Dawley rats but was not altered in Wistar rats. "Theoretical" values of microsomal epoxidase activity were calculated for weanling and adult Sprague-Dawley rats from turnover numbers and published data on the relative abundance of aldrin epoxidizing P-450 isozymes (Waxmann et al., Biochemistry 24, 4409, 1985). These values agreed with the activities determined. A similar statement can be made for male rats of both strains pretreated with inducers, when the ratio of enzyme activity of pretreated to control animals was used as a basis of comparison. The activity ratio of females pretreated with pregnenolone-16-alpha-carbonitrile, dexamethasone and phenobarbital, however, was much higher than the ratio calculated. Our results reveal that aldrin epoxidation is a reaction indicative of male specific and of phenobarbital-inducible cytochrome P-450 isozymes in rat liver.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Rat liver cytochrome P-450 isozymes as catalysts of aldrin epoxidation in reconstituted monooxygenase systems and microsomes. 360 56

The experiments on rats have shown that alpha-tocopherol and lidocaine pretreatment leads to a decrease in the level of ischemic cell necrosis in the liver. The volume of cell necrosis in the liver was significantly decreased (more than threefold) in the case of drug pretreatment. The combination of alpha-tocopherol with lidocaine fully prevented the decrease in N-dimethylation of amidopyrine and cytochrome P-450 and b5 concentration, and the development of destructive alterations of cytoplasmic reticulum in the unaffected rat hepatocytes. alpha-Tocopherol and lidocaine pretreatment was effective for the retention of the depression of microsomal monooxygenases by phenobarbital in remote periods after acute hepatic ischemia.
 ...
PMID:[Prevention, using alpha-tocopherol and lidocaine, of damage to the monooxygenase system activity and ultrastructure of hepatocytes following acute ischemia of the liver]. 368 56

Correlation between antitumor activity and effects on some biological properties, such as phagocytic activity of the reticuloendothelial system, the third component of complement (C3) activation, hepatic drug-metabolizing activities and pentobarbital-induced narcosis, of antitumor agents from various natural sources such as B B (Broncasma Berna), GU-P (Grifora umbellata polysaccharide), OK-432, PS-K (Polysaccharide Kureha), and RA-P (Rumex acetosa polysaccharide) were studied with female ICR mice implanted with Sarcoma 180 solid tumor. All of these agents depressed aniline hydroxylase and aminopyrine demethylase activities, prolonged the duration of pentobarbital-induced narcosis, and significantly enhanced the phagocytic activity and C3 activity. Especially, RA-P which has the strongest antitumor activity was the most effective in changing these activities. The biological activities of GU-P at a dose of 10 mg/kg reached the same level as that found with PS-K at a dose of 100 mg/kg. a possible mechanism of inhibition of Sarcoma 180 solid tumor growth by the treatment with the antitumor agents could be interpreted as due to the C3 activation, the stimulation of phagocytic activity and depression of the hepatic microsomal drug-metabolizing system in tumor-bearing mice.
 ...
PMID:Effects of the antitumor agents from various natural sources on drug-metabolizing system, phagocytic activity and complement system in sarcoma 180-bearing mice. 371 70


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>