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1.
Low molecular weight polar complexes were shown to be formed from 3H-aldosterone in both kidney and liver subcellular fractions, the majority being present in the cytosol fractions. Significant differences were observed between the quantities of polar complexes present in kidney subcellular fractions from intact and adrenalectomized male rats and also between the quantities of these kidney polar complexes from spironolactone treated male rats. 3H-aldosterone macro-molecule complexes were shown to exist in appreciable quantities only in the kidney cytosol fractions of adrenalectomized male rats. These gel filtration studies also showed the 3H-aldosterone labeled macromolecule complexes to consist of two protein peaks; one of high molecular weight and the other of lower molecular weight (~50,000 mol. wt.). The amount of 3H-aldosterone labeled protein complexes in kidney cytosol was greatly reduced when adrenalectomized rats were pretreated with spironolactone. 相似文献
2.
H A Sasame J R Gillette M R Boyd 《Biochemical and biophysical research communications》1978,84(2):389-395
An antibody prepared against purified rat liver NADPH-cytochrome reductase inhibited both the pulmonary and hepatic microsomal covalent binding of 4-ipomeanol as well as the respective NADPH-cytochrome reductase activities, findings which are consistent with previous studies which indicated the participation of cytochrome P450 in the metabolic activation of the toxin. An antibody prepared against purified rat liver cytochrome b5, which strongly inhibited both the rat hepatic and pulmonary NADH-dependent cytochrome reductases, and was inactive against the respective NADPH-dependent cytochrome reductases, had little effect on metabolic activation of 4-ipomeanol by hepatic microsomes, but strongly inhibited both the NADH-supported and the NADPH-supported pulmonary microsomal metabolism and covalent binding of the compound. These results suggest that metabolic activation of 4-ipomeanol involves a two-electron transfer in which transfer of the second electron via cytochrome b5 is rate-limiting in lung microsomes. 相似文献
3.
Incorporation of C14 Leucine was determined or in isolated mitochondria and microsomes of rat brain and liver after acute or chronic ethanol administration .The protein synthesis in mitochondrial and microsomal preparation was inhibited respectively by chloramphenicol and cycloeximide, specific inhibitors for the two systems tested. The experimental data demonstrate that the protein synthesis in both systems, mitochondrial and microsomal, is strongly affected only after chronic treatment which produces significant activation at the mitochondrial and microsomal level in the liver and an inhibition on the same systems of the brain.The data for protein synthesis instead show strong inhibition after acute administration, except for brain mitochondria, which are practically unaffected, while after chronic treatment no significant alterations are observed. 相似文献
4.
The effect of (?)-Δ9-THC on the activities of Mg2+?, Na+?K+? and Mg2+Ca2+-ATPases were studied in mouse brain subcellular fractions. treatment with Δ9-THC produced a dose dependent stimulation of Mg2+ ATPase in the crude mitochondrial fraction and its subfractions and a dose-related inhibition of this activity in the microsomal fraction. Na+-K+- and Mg2+-Ca2+-ATPase activities were inhibited in a dose-related manner in all subcellular fractions studied. 相似文献
5.
The cellular distribution of 35S from 35S- thioacetamide was determined in rabbit liver subcellular fractions following its administration. Of the various fractions isolated, only the nucleolar fraction contained 35S counts that were insoluble in 10% trichloroacetic acid but soluble in trichloroacetic acid if the fraction was treated with trypsin but not RNase or DNase. These results demonstrate that a protein bound form of thioacetamide is present in the nucleolus following administration of this drug. 相似文献
6.
effects of toxaphene on Ca2+-ATPase activity and 45Ca2+-uptake were studied in mitochondrial fractions of heart, kidney and liver tissues of rat. Mitochondrial fractions were prepared by the conventional centrifugation method. Ca2+-ATPase activity was determined by measuring the inorganic phosphate liberated during ATP hydrolysis. Toxaphene inhibited Ca2+-ATPase in a concentration dependent manner in all the three tissues. Substrate activation kinetics, with heart, kidney and liver tissue fractions, revealed that toxaphene inhibited Ca2+-ATPase activity non-competetively by decreasing the maximum velocity of the enzyme without affecting the enzyme-substrate affinity. Toxaphene also inhibited mitochondrial 45Ca2+-uptake in the three selected tissues in a concentration dependent manner. These results indicate that toxaphene is an inhibitor of mitochondrial Ca2+-ATPase and calcium transport in heart, kidney and liver tissues of rat. 相似文献
7.
S K Hanson M W Anders M R Montgomery 《Biochemical and biophysical research communications》1978,85(2):783-787
Oxygen metabolism has been quantified in rabbit bone marrow and liver. NADPH-Cytochrome reductase activity in bone marrow microsomal and cytosol fractions was about 40% of that found in liver. Superoxide anion and peroxide generation were found to be present in both liver and bone marrow. Catalase and superoxide dismutase activity were measured in liver and in marrow preparations free of erythrocytes; while liver catalase activity was approximately twice that of bone marrow, very low superoxide dismutase activity was observed in erythrocyte free bone marrow homogenates. 相似文献
8.
In order to define the site of bioactivation of CCl4, CHCl3 and CBrCl3 in the NADPH cytochrome reductase-cytochrome P-450 coupled systems of liver microsomes, the 14C-labeled hepatotoxins were incubated with isolated rat liver microsomes and a NADPH-generating system. The covalent binding of radiolabel to microsomal protein was used as a measure of the conversion of the hepatotoxins to reactive intermediates. Omission of NADPH, incubation under CO:O2 (8:2) and addition of a cytochrome reductase specific antisera mardedly reduced the covalent binding of all three compounds. When cytochrome P-450 was reduced to less than 25% of normal by pretreatment of rats with allylisopropylacetamide (AIA), but cytochrome reductase activity was unchanged, the covalent binding of CCl4, CHCl3, and CBrCl3 was decreased by 63, 83, 70%, respectively. Incubation under an atmosphere of N2 enhanced the binding of CCl4, inhibited the binding of CHCl3 and did not influence the binding of CBrCl3. It is concluded that cytochrome P-450 is the site of bioactivation of these three compounds rather than NADPH cytochrome reductase and that CCl4 bioactivation proceeds by cytochrome P-450 dependent reductive pathways, while CHCl3 activation proceeds by cytochrome P-450 dependent oxidative pathways. 相似文献
9.
Man is exposed to epoxides of fatty acids from a number of sources, yet their degradative metabolism is not well understood. In mouse liver the 100,000 g supernatant or the cytosolic fraction is the most active fraction in hydrating - and -epoxymethyl stearates with the oxirane ring opening in a manner to give the corresponding and diols, respectively. Hydration was also observed in the microsomal, nuclei and cell debris, and mitochondrial fractions in decreasing order of specific activity. 相似文献
10.
Seiko Kyakumoto Nobuko Sato Takayuki Nemoto Yuko Ohara-Nemoto Minoru Ota 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,800(3):214-219
The synthetic androgen methyltrienolone is superior to testosterone and androstenedione for the measurement of androgen receptor in tissues where the native ligands are metabolized into inactive derivatives. [3H]Methyltrienolone binds with a high affinity to androgen receptor in cytosol prepared from male rat livers, as the Scatchard analysis revealed that the Kd value was 3.3 · 10?8 M and the number of binding sites was 35.5 fmol/mg protein. Since methyltrienolone also binds glucocorticoid receptor which exists in rat liver, the apparent binding of androgen receptor is faulty when measured in the presence of glucocorticoid receptor. The binding of methyltrienolone to glucocorticoid receptor can be blocked by the presence of a 100-fold molar excess of unlabeled synthetic glucocorticoid, triamcinolone acetonide, without interfering in its binding to androgen receptor, because triamcinolone does not bind to androgen receptor. Triamcinolone-blocked cytosol exhibited that the Kd value was 2.5 · 10?8 M and the number of binding sites was 26.3 fmol/mg protein, indicating a reduction to of that in the untreated cytosol. The profile of glycerol gradient centrifiguration indicated that [3H]methyltriemolone-bound receptor migrated in the 8–9 S region in both untreated and triamcinolone-blocked cytosols, but the 8–9 S peak in triamcinolone-blocked cytosol was reduced to about of that of untreated cytosol. 相似文献
11.
Tissue copper levels of brindled (br) mice and normal litter-mates after single and repeated dosing with CuCl2 and/or D-penicillamine are examined, together with a study of the cytosol distribution of copper after CuCl2 treatment. The results confirm that the mutant mouse kidney is capable of extensive copper accumulation in association with the low MW copper-binding protein. Deficient tissues such as brain, heart and spleen are able to sequester sufficient of the exogenous copper to raise their levels to the normal control level, whereas mutant liver levels, even after copper treatment, remain below normal, indicating that the gene affects the ability of the liver to retain copper. 相似文献
12.
Dystrophic mice of the C57B1 strain and of the ReJ 129 strain and littermate controls were used to prepare met-tRNAfMet binding factors. The tissues were homogenized and fractions were obtained which contained ribosomes. The binding factors were assayed by the binding of [35S]methionyl-tRNA to control liver ribosomes. The binding, i.e. eukaryotic initiation factor 2 (elF 2) activity, was measured in brain, liver and muscle and in all of these tissues there was a significant decrease in the dystrophic mice. This decrease in initiation factor activity of hindleg muscle resembled, in the direction of the effect, the decrease in elongation factor activity of hindleg muscle resembled, in the of mice previously reported by our laboratory. Thus these two defects, taken together may help to explain the marked wasting of the muscles. The decrease in brain in both strains provides evidence for nervous tissue involvement in genetic dystrophy. 相似文献
13.
Rat liver cytosol binds 3H-cAMP and 3H-DBcAMP . Fractionation of bound radioactivity by DEAE-Sephadex chromatography shows that 3H-cAMP is associated with a different cytosolic protein than is 3H-DBcAMP. The pI's of the cAMP-protein and the 3H-DBcAMP-protein complexes are 6.7 and 3.9, respectively. Competition studies between 3H-cAMP and its structural analogues have shown the following order of effectiveness in competing for binding sites in rat liver cytosol: cAMP > N6-MBcAMP > O2′-MBcAMP. No inhibition of 3H-cAMP binding was observed with 5′-AMP, adenosine, cGMP or DBcAMP. binding experiments with rat serum has shown that only 3H-DBcAMP binds to any significant extent. 相似文献
14.
The covalent binding of metabolically activated 1,2-dibromoethane (DBE), a potent carcinogen, to chromatin constituents of forestomach and liver was examined . Chromatin was prepared from forestomach and liver of B6C3F1 mice and characterized. In order to activate DBE, microsomes and cytosol were isolated from mouse forestomach and liver and incubated with [14C]-DBE in the presence of a NADPH regenerating system. Results demonstrate that DBE bound covalently to the same extent to protein of microsomes and chromatin isolated from forestomach and liver. On the contrary, DBE bound significantly more to chromatin DNA of forestomach or liver than it did to salmon sperm DNA. It appears from these results that the metabolically activated DBE is more reactive to homologous DNA than exogenous DNA. Fractionation of DBE-bound chromatin protein into histone and nonhistone proteins resulted in higher binding of DBE to non-histone than to histone proteins isolated from forestomach and liver. 相似文献
15.
A component which can bind retinol and fatty acids was detected in the rat's intestinal cell cytosol following intestinal perfusion with 3H-all-trans retinol. Following Sephadex G-100 filtration of the cytosol, the void volume concentrate was treated with 2-mercaptoethanol and SDS. Sephadex G-100 filtration of the concentrate disclosed the presence of a cytosol binder of an approximate molecular weight of 12,000–17,000. The binder contained most of the 3H-retinol eluted off the column. incubation experiments disclosed that 3H-retinol could be displaced from its bindinf cytosol fraction by the addition of nonradioactive retinol, retinyl acetate, and the fatty acids octanoic, linoleic, and linolenic. Butyric acid addition did not displace 3H-retinol from its binding fraction. The intestinal cytosol binding fraction may be involved in the trans-cytosol transport of lipid compounds from the lipid cell membrane to the intracellular organelles. 相似文献
16.
B.K. Semin A.A. Novakova A.Yu. Aleksandrov I.I. Ivanov A.B. Rubin R.N. Kuzmin 《Biochimica et Biophysica Acta (BBA)/General Subjects》1982,715(1):52-56
Mössbauer spectroscopy was used to investigate the distribution of iron in rat organs and its localisation in liver subcellular fractions. A 57Fe-sucrose complex solution was injected by 0.5 ml doses into tail veins of anmals every day, during a 6-day period. Mössbauer spectra were measured in spleen, blood, liver and liver subcellular fractions. The Mössbauer spectrum of a spleen sample has two symmetrical doublets, one with δ=0.6 mm/s and Δ=0.7 mm/s, and the other with δ=1.0 mm/s and Δ=2.35 mm/s. The Mössbauer spectrum of blood has parameters which are close to those for carboxyhemoglobin and oxyhemoglobin complexes. After the addition of sodium citrate, the proportion of the carboxyhemoglobin complexes increases. The Mössbauer spectrum of liver has a two-component pattern with two symmetrical doublets, the first with δ=0.6 mm/s and Δ=0.63 mm/s and the second with δ=1.4 mm/s and Δ=3.45 mm/s. The first component, which was identified as ferritin, is present in all subcellular fractions (800 × gav sediment fraction, mitochondrial/lysosomal, microsomal and supernatant fractions), with its content in microsomal fraction. After the addition of NaBH4 to mitochondrial/lysosomal fraction, about 20 % of the iron contained in ferritin was reduced. In the Mössbauer spectrum this is reflected by an appearance of a doublet with δ=0.85 mm/s and Δ=3.7 mm/s. 相似文献
17.
Transfer of phospholipids between the endoplasmic reticulum and mitochondria in rat hepatocytes in vivo 总被引:1,自引:0,他引:1
I Eggens C Valtersson G Dallner L Ernster 《Biochemical and biophysical research communications》1979,91(3):709-714
The transfer of phospholipids from the endoplasmic reticulum to the inner mitochondrial membrane was investigated by pulse labeling . With [3H]glycerol microsomal phosphatidylethanolamine and phosphatidylcholine were rapidly labeled during the first 30 min; while maximum incorporation into the inner mitochondrial membrane occurred only after about 5 hours. It appears that the transfer of these phospholipids between the two membrane compartments is a relatively slow process. 相似文献
18.
Different glycosides were grafted on the surface of liposomes containing 125I-labelled γ-globulin by two ways: (1) by using glycolipid and (2) by covalent coupling of to phosphatidylethanolamine liposomes using glutaraldehyde. The distribution of 125I-labelled γ-globulin was determined in mouse tissues from 5–60 min after a single injection of these liposomes. The liver uptake of encapsulated 125I-labelled γ-globulin was highest from liposomes having galactose and mannose on the surface. Competition experiments and cross-inhibition studies indicate that this uptake are mediated by specific recognition of the surface galactose and mannose residues of liposomes by the receptors present on the plasma membrane of liver cells. Stearylamine-containing liposomes were found to be more efficient in mediating the uptake of 125I-labelled γ-globulin by the lung, whereas in the case of spleen, phosphatidylethanolamine liposomes were more efficient. The extent of uptake of 125I-labelled γ-globulin from all types of liposome decreases as the amount of given liposomes increases. The uptake of 125I-labelled γ-globulin from liposomes containing asialogangliosides depends upon the phospholipid/ glycolipid ratio. These experiments clearly demonstrate that enhanced liposome uptake by liver cells could be achieved by grafting galactose and mannose on the liposomal surface. 相似文献
19.
The effect of certain DDT analogs on the binding of 3H-estradiol to the 8–9S estrogen binding protein of rat testicular cytosol was studied by sucrose sedimentation analysis. The binding of 3H-estradiol to testicular cytosol was inhibited by o,p'DDT, a DDT analog which is estrogenic in the intact female, but not by p,p'DDE which is a nonestrogen in the female. The pesticide methoxychlor, which is estrogenic in the female, failed to inhibit 3H-estradiol binding, presumably requiring metabolic activation for binding to the testicular cytosol. In fact, its di-demethylated metabolite 2,2-bis(p-hydroxyphenyl)-1, 1,1-trichloroethane (HPTE), also estrogenic , caused suppression of 3H-estradiol binding. 相似文献
20.
Nuclear binding of corticosteroids in fish tissues was investigated in two target organs of the trout : the liver and the intestinal mucosa. Incubation of intact nuclei with [3H]-cortisol or [3H]-dexamethasone failed to demonstrate high-affinity binding of these steroids to proteins. Exchange assay of [3H]-cortisol in high-salt nuclear extracts indicated an association constant Ka = 1.9 × 104 M?1 for intestinal mucosa and 2.1 × 104 M?1 for liver. In sea water-adapted trout, the association constant remained the same as in fresh water.These results extend previous observations obtained on the cytosol which showed that no high-affinity receptors could be disclosed in fish tissues using these two corticosteroids. 相似文献