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1.
T Shiratori 《Life sciences》1974,14(5):929-935
Tritium- -tocopherol was incorporated into chylomicra by feeding dl-α-(5 methyl 3H)-tocopherol to rats with thoracic duct cannulae. Tritium α-tocopherol in chylomicra, isolated by flotation through 0.85% NaCl, was injected intravenously into rats and distribution of radioactivity was followed in skin, viscera and carcass. Label measured at 112, 1, 3, 10 and 20 days following injection demonstrated a rapid uptake and prolonged retention in skin compared to viscera and carcass. In fact, relative distribution in skin increased from an average of 10.3% at 112day to 40.1% of the recovered dose at 20 days. Also, the uptake of isotope by skin, expressed as 3H dpm/g lipid, markedly exceeded that of epididymal fat suggesting a preferential distribution to cutaneous tissue. Significant radioactivity was found on the skin surface and hair following injection of 3H-α-tocopherol demonstrating the excretion or secretion of vitamin E compound(s) by the skin.  相似文献   

2.
In the present study the effect of intracerebroventricularly (ICV) administered somatostatin on electroconvulsive shock- (ECS) induced retrograde amnesia was investigated in rats. The ECS significantly decreased foot shock-induced avoidance latency. Somatostatin in a dose of 1 μg4 μl (ICV) had no action on the ECS-induced retrograde amnesia, while in a dose of 4 μg4 μl it significantly increased the avoidance latency if the treatment was performed immediately, 4 hr, 20 hr or 23 hr after the ECS. The results suggest that ICV administered somatostatin has an antiamnesic effect.  相似文献   

3.
The present study was conduced to investigate the synergistic effects of combined treatments with Se-methylselenocysteine (SeMSC) and vitamin E (Vit E) in reversing oxidative stress induced by ethanol in serum and different tissues of rats. Sixty female rats were randomly divided into six groups for 30 days’ consecutive pretreatments as followed: control (I), physiological saline (II), 2.8 μg kg−1 Se as SeMSC (III), 2.8 μg kg−1 Se as sodium selenite (Na2SeO3, IV), 5 mg kg−1 α-tocopherol as α-tocopherol acetate (Vit E, V), 5 mg kg−1 α-tocopherol as α-tocopherol acetate and 2.8 μg kg−1 Se as SeMSC (VI). All animals in groups II–VI were treated by ethanol treatment to cause oxidative stress. After 6 h of ethanol treatment, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), the contents of total antioxidant capacity (T-AOC), malondialdehyde (MDA), glutathione (GSH) and carbonyl protein (CP) in the serum, liver, heart and kidney were measured. The result showed that the individual SeSMC, Na2SeO3 and vitamin E could effectively increase the SOD, T-AOC, GSH-Px and GSH contents as well as significantly decrease the MDA and CP concentrations in the tissues of ethanol-induced rats. At the same dose on different forms of Se, SeMSC showed greater antioxidant activity than Na2SeO3. Moreover, group VI (SeMSC and α-tocopherol acetate) showed much better antioxidant activity than individual group III (SeMSC) and V (α-tocopherol acetate) due to the synergistic effect.  相似文献   

4.
A. Telfer  J. Barber 《BBA》1978,501(1):94-102
1. Ionophore A23187 induces uncoupling of potassium ferricyanide-dependent O2 evolution by envelope-free chloroplasts and oxaloacetate-dependent O2 evolution by intact chloroplasts. The half maximal concentration (C12) for stimulation of oxygen evolution in both cases is approximately 4 μM · 100 μg chlorophyll · ml?1.2. Ionophore A23187 also induces inhibition of CO2 and 3-phosphoglycerate-dependent O2 evolution by intact chloroplasts in the presence of 3 mM MgCl2. The half maximal concentrations (C12) for inhibition of O2 evolution are 3 μM and 5 μM respectively · 100 μg?1 chlorophyll · ml?1.3. A very high concentration of ionophore A23187 (10 μM · 20 μg?1 chlorophyll · ml?1) plus 0.1 mM EDTA lowers the fluorescence yield of intact chloroplasts suspended in a cation-free medium in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea, indicating loss of divalent cation from the diffuse double layers of the thylakoid membranes.4. These results are discussed in relation to ionophore A23187-induced divalent cation/proton exchange at both the thylakoid and the envelope membranes of intact chloroplasts.  相似文献   

5.
Chlordecone greatly potentiates carbon tetrachloride (CC14) hepatotoxicity. In order to quantitate the degree of this potentiation, the effects of a range of doses of CC14 on two microsomal enzymatic functions and liver enzyme release were examined in chlordecone-treated and control rats. Male Sprague-Dawley rats were pretreated with 15 mg chlordecone per kilogram body weight (BW) intragastrically or with vehicle. After 48 hours, 0 to 250 μ1 CC14 per 100 g body weight were given intraperitoneally (IP), and the rats were killed 24 hours later. Chlordecone treatment produced approximately a 17-fold potentiation of the CC14 dependent loss of cytochrome P-450 and glucose-6-phosphatase activity, so that a dose of 6 μ1 CC14 per 100 g body weight in the chlordecone-treated animals resulted in a similar amount of damage as observed with 100 μ1 CC14 per 100 g body weight in controls. A similar potentiation by chlordecone was seen with CC14- induced increases in serum glutamic-oxaloacetic transaminase (SGOT) levels. Chlordecone treatment also increased hepatic cytochrome P-450 levels by 67% and resulted in an increase in the covalent binding of [14-C]-CC14-derived metabolites to microsomal protein and lipid in vivo.  相似文献   

6.
Hemolytically active components from P. parvum and G. breve toxins   总被引:1,自引:0,他引:1  
Y S Kim  G M Padilla 《Life sciences》1977,21(9):1287-1292
Hemolytically active fractions were isolated from the toxins produced by the red-tide dinoflagellate Gymnodinium breve (GBTX) and the chrysomonad Prymnesium parvum (PPTX). High pressure liquid chromatography through bonded phase (ODS) silica columns using a gradient of methanol in chloroform yielded 6 major fractions from GBTX, 3 of which were hemolytic (HD50=0.3?0.56 μg·ml?1). None were ichthyotoxic. Of the 6 fractions obtained from PPTX, 4 were hemolytic (HD50=0.013?2.8 μg·ml?1) but only one (fraction 6) was ichthyotoxic. This fraction was ~ 2000 times more hemolytic than the crude PPTX (HD50=33.2 μg·ml?1). Analysis of their UV spectra indicates that the fractions within each group are closely related.  相似文献   

7.
The hypoglycemic agent, 2-tetradecylglycidic acid (TDGA), administered in vivo lowered the concentration of plasma glucose and ketone bodies but raised the concentration of liver and plasma triglycerides in 10-day-old suckling rats. Phospholipid and cholesterol content of the plasma and liver were unaffected by drug treatment. TDGA inhibited the in vivo oxidation of [1-14C]palmitate but not that of [1-14C]decanoate. In suckling rat liver perfusion, TDGA totally inhibited ketone body formation from palmitate and depressed ketone body production from decanoate by 20%. Liver ATP and ADP content in the presence of TDGA decreased although this was probably a reflection of the increased triglyceride content of the liver since the ATPADP was the same as control livers. The results are discussed in relation to the diet and to the inhibition of carnitine acyl transferase in suckling rats.  相似文献   

8.
The effects of thyroxine (T4) and methimazole administration on plasma prostacyclin (PGI2) levels in vivo and on PGI2 release by aortic rings incubated in vitro were investigated in rats. Male rats were given single injection of T4 (200 μg/100 g body wt) ip every 24 h for either 3, 7 or 14 days for hyperthyroid rats. For hypothyroid rats, a group of rats were given methimazole (0.01 % in drinking water) for 14 days. PGI2 concentrations were determined in plasma and also in the medium in which aortic rings were incubated. PGI2 was measured as 6-keto-PGF1α by RIA. Plasma PGI2 levels in T4-treated groups were found to be significantly higher than those of control animals. Aortic rings obtained from rats given single injection of T4 for 7 and 14 days showed significant increases in release of PGI2 into the incubation medium. In contrast, rats given methimazole for 14 days showed a significant decrease in the production of PGI2 by aortic rings without any significant changes in plasma levels. Direct addition of T4 into the incubation medium did not cause any significant changes in PGI2 release by aortic rings obtained from control rats.These results suggest the regulatory role of thyroid hormone in PGI2 synthesis in vivo.  相似文献   

9.
ω6- and ω3-unsaturated lipid hydroperoxides decompose to yield pentane and ethane, respectively. Alloxan toxicity was studied in rats in relation to pentane and ethane produced during lipid peroxidation induced by intraperitoneal injection of 20 mg of alloxan/100 g body wt. Fifteen minutes after injection, vitamin E-deficient rats exhaled 102- and 11.2-fold more pentane and ethane, respectively, than prior to injection. Injection of 75 mg ascorbic acid/100 g body wt 30 min prior to alloxan treatment prolonged the time over which peroxidation occurred and all vitamin E-deficient rats died before 4 h. Vitamin E-deficient rats injected with 100 mg of the radical scavenger mannitol/ 100 g body wt 30 min prior to alloxan treatment were completely protected against lipid peroxidation, and none of the rats died by 4 h. Rats fed 40 iu dl-α-tocopherol acetate/kg diet or injected with 100 mg dl-α-tocopherol/100 g body wt were either totally protected against alloxan and alloxan-ascorbic acid-induced peroxidation or were only slightly affected as shown by very low-level pentane and ethane production. Thiobarbituric acid reactants in plasma, liver and pancreas 4 h after alloxan treatment reflected the prooxidant nature of ascorbic acid and alloxan, the vitamin E status of the rats and the protective effect of mannitol. Plasma glucose levels 4 h after alloxan injection were lowest in vitamin E-injected rats and highest in vitamin E-deficient rats. Only in vitamin E-deficient rats were both lipid peroxidation and significantly elevated plasma glucose levels observed by 4 h post-alloxan treatment.  相似文献   

10.
Acetylcholine receptor from Torpedo californica can be incorporated by the cholate dialysis procedure into liposomes prepared with crude soybean phospholipids (asolectin). Vesicles reconstituted with asolectin depleted of neutral lipids or with a mixture of pure phospholipids, are less active in catalyzing carbamylcholine-sensitive Na+ flux. Inclusion of α-tocopherol or certain quinones such as coenzyme Q10 or vitamin K1 during reconstitution yields vesicles with carbamylcholine-sensitive Na+ flux which, under optimal conditions, was considerably higher than that observed with vesicles reconstituted with crude phospholipid mixtures.  相似文献   

11.
Liver extracts (8000 × g for 10 min) from fasted rats contain about 4 times more phosphorylase phosphatase activity when the liver was homogenized in a hypotonic medium or frozen before homogenization. This increase is caused by: (i) release of partially latent phosphatases (Mr=60 000 and 45 000 in sucrose gradient centrifugation) from ruptured organelles; (ii) rapid activation of phosphatase in the ruptured pellet by endogenous protease(s) which can be blocked by p-tosyl-L-lysine chloromethyl ketone. Only the Mr=60 000 enzyme, associated with the nuclei, can be activated proteolytically, with conversion to an Mr=45 000.  相似文献   

12.
The number of tetrathyridia in the peritoneal cavities of mice increases exponentially with time. Thirty days post infection more larvae are in the cavities than in the livers. After that the increase of intraperitoneal populations continues, whereas the number of tetrathyridia in the livers remains more or less constant.Exogenous testosterone propionate, 10 μgg, twice a week, for 5 weeks, increases significantly the total volumes of tetrathyridial populations in the peritoneal cavities, whereas oestradiol benzoate, 5 μgg or 10 μgg, also for 5 weeks, accelerates the rate of growth and multiplication of coelomic tetrathyridia to a much lesser extent, but increases significantly the infection of the livers.  相似文献   

13.
Low-density lipoprotein (LDL) oxidation is the primary event in atherosclerosis, and LDL lipoperoxidation leads to modifications in apolipoprotein B-100 (apo B-100) and lipids. Intermediate species of lipoperoxidation are known to be able to generate amino acid-centered radicals. Thus, we hypothesized that lipoperoxidation intermediates induce protein-derived free radical formation during LDL oxidation. Using DMPO and immuno-spin trapping, we detected the formation of protein free radicals on LDL incubated with Cu2+ or the soybean lipoxidase (LPOx)/phospholipase A2 (PLA2). With low concentrations of DMPO (1 mM), Cu2+ dose-dependently induced oxidation of LDL and easily detected apo B-100 radicals. Protein radical formation in LDL incubated with Cu2+ showed maximum yields after 30 min. In contrast, the yields of apo B-100 radicals formed by LPOx/PLA2 followed a typical enzyme-catalyzed kinetics that was unaffected by DMPO concentrations of up to 50 mM. Furthermore, when we analyzed the effect of antioxidants on protein radical formation during LDL oxidation, we found that ascorbate, urate, and Trolox dose-dependently reduced apo B-100 free radical formation in LDL exposed to Cu2+. In contrast, Trolox was the only antioxidant that even partially protected LDL from LPOx/PLA2. We also examined the kinetics of lipid radical formation and protein radical formation induced by Cu2+ or LPOx/PLA2 for LDL supplemented with α-tocopherol. In contrast to the potent antioxidant effect of α-tocopherol on the delay of LDL oxidation induced by Cu2+, when we used the oxidizing system LPOx/PLA2, no significant protection was detected. The lack of protection of α-tocopherol on the apo B-100 and lipid free radical formation by LPOx may explain the failure of vitamin E as a cardiovascular protective agent for humans.  相似文献   

14.
A highly purified and active cytochrome b-c1 complex has been isolated from the chromatophores of the photosynthetic bacteria Rhodopseudomonassphaeroides R-26, through steps of Triton X-100 solubilization, salt fractionation and calcium phosphate column chromatography. The isolated enzyme complex catalyzes fully antimycin A sensitive oxidation of ubiquinol by cytochrome c with a turnover number of 1500 per minute at 23° based on cytochrome c1. It contains 8.3 nmoles of cytochromes b and c1 per mg protein and shows four polypeptides in the sodium dodecylsulfate polyacrylamide gel electrophoresis.  相似文献   

15.
Male, albino, Sprague-Dawley rats were sacrificed by cervical separation. Segments of jejunum were excised, everted and examined with the electron microscope. Examination of tissue fixed immediately after eversion revealed the following changes as compared to non-everted segments fixed insitu and invitro: 1) an increase in the length of microvilli from (mean ± S. E.) 0.991 ± 0.011μ for normal tissue to 1.389 ± 0.023μ for everted tissue, 2) an increase in width of microvilli from (mean ± S. E.) 0.089 ± 0.001μ for normal tissue to 0.097 ± 0.001μ for everted tissue, 3) an increase in length and number of lateral membrane interdigitations, and 4) the appearance of intercellular “lakes” in the lateral spaces. The above changes are in those structures hypothesized to be involved with salt and water transport across epithelia and may reflect altered transport rates invitro as compared to invivo.  相似文献   

16.
An iron-sulfur protein has been isolated from bovine liver mitochondria and purified 140-fold on DEAE-cellulose and Sephadex G-100. During the isolation the protein was detected by its NADPH-cytochrome c reductase activity in the presence of adrenal NADPH-ferredoxin reductase. The molecular weight of the protein (12,400), the optical spectrum (peaks at 414 nm and 455 nm which disappear upon reduction), and the EPR spectrum (gx = gy = 1.935 and gz = 2.02) were typical for a ferredoxin. In the presence of soluble adrenal cytochrome P450, ferredoxin reductase and NADPH, this protein could support the formation of pregnenolone from cholesterol. Under similar conditions, but in the presence of a cytochrome P450 solubilized from rat liver mitochondria, cholesterol was transformed into a more polar compound tentatively identified as 26-hydroxycholesterol.  相似文献   

17.
Cytochrome P1-450 (P1-450) is defined as that cytochrome most closely associated with 3-methylcholanthrene (MC)-induced aryl hydrocarbon hydroxylase (AHH) activity. Recently a cloned DNA sequence (clone 46) was shown to represent a portion of the P1-450 structural gene [Negishi etal., Proc. Nat. Acad. Sci. U.S.A.78: 800–804 (1981)]. Poly(A+)-enriched RNA was isolated from total liver homogenate, membrane-bound polysomes and from free polysomes at various times after MC treatment of Ah-responsive C57BL6N (B6) and Ah-nonresponsive DBA2N (D2) inbred mice. The poly(A+)-enriched RNA was separated by methylmercury-agarose gel electrophoresis and hybridized to nick-translated [32P]DNA from clone 46. By means of this RNA-DNA hybridization, only 6% of total polysomal P1-450 mRNA exists in free polysomes after 24 h of MC treatment. The data indicate that the endoplasmic reticulum is the principal site of synthesis for this integral microsomal protein.Studies of induction kinetics following MC treatment provided the evidence of the rapid increase of total liver and membrane bound P1-450 mRNA preceding the synthesis of apo-P1-450 and the increase of AHH activity.  相似文献   

18.
19.
After a single injection of Cerium chloride to female rats, liver triglycerides concentration increases sharply and plasma lipids decrease to about one half the initial level. In these conditions, the respiratory quotient of treated rats invivo decreases by 20% indicating a lowered fatty acid oxidation. Incorporation of [3H]-oleate into liver lipids shows an important accumulation of newly synthetized triglycerides without any significant effect on phospholipids. Lipoproteins production estimated by [3H]-oleate and [14C]-leucine incorporation into plasma very low-, low- and high-density lipoproteins shows a 50% inhibition synthesis of lipoprotein.  相似文献   

20.
Quenching of singlet molecular oxygen (1ΔgO2) by α-tocopherol (I) involves the hydroxy function of the chromanol ring of I. In phosphatidylcholine (PC) uni- and multilamellar vesicles this structural element of I is localized at the interface polar headgroup/hydrophobic core. A dielectric constant of ? ~ 25 was determined for this special region of the PC bilayer. The ratio kQ/kR of rate constants of quenching processes (kQ) and irreversible reactions (kR) of I with 1ΔgO2 increases with decreasing polarity of the solvent. In ethanolic solutions where ? = 25.5, kQ/kR is about 40. Extrapolation of these results to phospholipid bilayers suggests that at the nearness of the ester carbonyl oxygen of the PC fatty acid moieties, α-tocopherol can deactivate approximately 40 1ΔgO2 molecules before being destroyed. It is concluded that in vivo, one may expect to find a higher kQ/kR ratio if the chromanol ring of I hides within the more hydrophobic interiors of the membrane surface peptides.  相似文献   

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