共查询到20条相似文献,搜索用时 31 毫秒
1.
The effects of 19-hydroxy-prostaglandins (19-OH-PGs) were tested on the rabbit oviduct and uterus and on the rhesus monkey () uterus. The 19-OH-PGEs suppressed spontaneous oviductal and uterine activity in the rabbit. The qualitative effect on the rabbit oviduct of 19-OH-PGEs was similar to that of PGE2. However, the typical response of the rabbit uterus to PGE2 was an increase in muscle activity. With regard to the rabbit oviduct, 19(R)-OH-PGE2 was as potent as PGE2, but 19(S)-OH-PGE2 was approximately as potent as PGE2. Based on the dose of 19-OH-PGEs usually required to cause a minimal suppression and the dose of PGE2 required to cause a minimal stimulation of rabbit uterine activity, 19(R)-OH-PGE2 was twice as potent as PGE2 while 19(S)-OH-PGE2 was as potent as PGE2. Stimulatory effects on the rabbit oviduct and uterus were observed following administration of 19-OH-PGEs and PGF2α. The potency on the rabbit oviduct of 19(S)-OH-PGF2α was about to that of PGF2α; the potency of 19(R)-OH-PGF2α was about to that of PGF2α. Both 19-OH-PGFs were approximately to as potent as PGF2α on the rabbit uterus. At the doses tested 19-OH-PGFs were inactive on the monkey uterus. Thus, these compounds are at least as active as PGF2α. In contrast, 19(R)-OH-PGE2 had approximately the same potency as PGE2 in stimulating monkey uterine activity; but 19(S)-OH-PGE2 was approximately as potent as PGE2. 相似文献
2.
OKY-1581 is an effective inhibitor of thromboxane synthesis and . The generation of thromboxane B2 (TxB2), prostaglandin E (PGE) and prostaglandin F (PGF) was measured following clotting and during platelet aggregation induced by collagen. The presence of OKY 1581 either or caused a reduction in TxB2 generation during clotting and platelet aggregation with a concomitant increase in PGE and PGF. The effect could be observed two hours after oral or subcutaneous administration of 5 to 100 mg per rabbit and lasted for 24 to 48 hours. The reduction in TxB2 was not accompanied by an inhibition of clotting or platelet aggregation. OKY-1581 appears to be a suitable agent for studying the role of TxB2 in atherosclerosis. 相似文献
3.
Effect of prostaglandin E2 on vascular responses of the rabbit kidney to nerve stimulation and noradrenaline, in vitro and in situ 总被引:2,自引:0,他引:2
The effect of prostaglandin E2 on vascular responses of the rabbit kidney to renal nerve stimulation and noradrenaline was examined and as a test of the hypthesis that prostaglandins of the E series may be involved in the regulation of adrenergic neuroeffector transmission. Intraarterial administration of prostaglandin E2 to the kidney caused marked inhibition of vascular responses to nerve stimulation whereas the responses to noradrenaline were not significantly altered. In the preparation, vascular responses to both nerve stimulation and noradrenaline were inhibited by prostaglandin E2 infusion, although its effect on responses to nerve stimulation was approximately twice that observed on responses to noradrenaline.It is concluded that prostaglandin E2 acts primarily at a prejunctional level of adrenergic neuroeffector transmission in the kidney, although a postjunctional effect has also been observed. 相似文献
4.
The role of cytochrome 5 in the -nitroanisole O-demethylation was studied with a reconstituted system containing a unique cytochrome P-450, isolated from rabbit liver microsomes as a species with a high affinity for cytochrome 5. The maximal activity was obtained in the complete system consisting of cytochrome P-450, NADPH-cytochrome P-450 reductase, NADH-cytochrome 5 reductase, and Triton X-100 in addition to cytochrome 5. The omission of cytochrome 5 from the complete system entirely abolished the activity. These results clearly show that cytochrome 5 is obligatory in the reconstitute p-nitroanisole O-demethylation system, and this cytochrome P-450 probably interacts with cytochrome 5 in such a way that the second electron is transferred from cytochrome 5 and thus exhibits the demethylase activity. 相似文献
5.
Elizabeth Adkins-Regan 《Behavioural processes》1985,11(2):153-158
This experiment examined the possibility that endogenous embryonic androgen contributes to sexual differentiation of behaviour in male or female quail (), and that it does so via aromatization (conversion to oestrogen). Eggs were injected on day 9 of incubation with oil or ATD (an aromatization inhibitor). As adults, males and females were exposed to short days, injected with testosterone propionate, tested for male-typical behaviour, then injected with oestradiol benzoate and tested for female-typical receptivity. ATD increased the level of male-typical copulatory behaviour in males. Male-typical behaviour in females was not affected, nor was female-typical behaviour in either sex. Thus normal male quail are actually slightly demasculinized by their own androgen during embryonic development, and this process is mediated by aromatization. 相似文献
6.
Synthesis of diphtheria toxin in E. coli cell-free lysate 总被引:7,自引:0,他引:7
An cell-free lysate was used to translate RNA from nontoxinogenic C7(?), C7 infected with β tox+ corynebacteriophage, and strain PW8. De novo synthesis of toxin was detected by immune precipitation with antitoxin, ADP-ribosylation of mammalian elongation factor 2 and rabbit skin test. The results indicated that toxin is produced in the protein synthesizing system primed with RNA from cells infected with tox+ bacteriophage and is absent in systems primed with RNA from C7(?) cells. 相似文献
7.
Yasuhiko Masuho Kazuo Kishida Takeshi Hara 《Biochemical and biophysical research communications》1982,105(2):462-469
The antiviral protein (PAP) of was conjugated with the Fab' fragment of IgG from a rabbit antiserum against murine leukemia L1210 cells via a disulfide bond employing -succinimidyl 3-(2-pyridyldithio)-propionate (SPDP) as the coupling agent. The conjugate showed a potent cytotoxicity against L1210 cells which was competitively blocked by F(ab′)2 directed against L1210 cells. PAP itself did not exhibit the cytotoxicity at the concentration corresponding to the PAP content in the conjugate concurrently tested. 相似文献
8.
A.W. Ford-Hutchinson A. Rackham R. Zamboni J. Rokach S. Roy 《Prostaglandins & other lipid mediators》1983,25(1):29-37
Synthetic leukotriene B4 (LTB4) and its ω-oxidation products, 20 OH-LT4 and 20 COOH-LTB4, were tested for their ability to induce the aggregation of rat neutrophils , to contract the guinea pig parenchymal strip and to cause vascular permeability changes in rabbit skin . 20 OH-LTB4 had 10, 100 and 20% of the activity of LTB4 in the neutrophil aggregation, parenchymal strip and vascular permeability assays respectively. 20 C00H-LTB4 was inactive and showed <1% of the activity of LTB4. These results show that while ω-oxidation is a route for biological inactivation of LTB4, 20 OH-LTB4 still retains significant biological activity. 相似文献
9.
The metabolism of drobuline has been examined in the dog, rabbit, rat, guinea pig and hamster. In the dog, unlike the other species, glucuronide conjugation is the major route of metabolism. The structure of the conjugate has been established as an O-glucuronide by isolation using HPLC following by field desorption mass spectral analysis. When the separate - and -isomers of drobuline were administered to a series of dogs the -isomer reached plasma levels approximately three time higher than those of the -isomer. Deuterium labeled drobuline was synthesized and resolved by multiple crystallizations of the malate salts. Racemic mixtures containing 6- and 6- drobuline and 6- and 6- drobuline were prepared and analyzed by GC-MS as the pentafluoropropionate derivatives. When either racemic mixture was administered to dogs (10 mg/kg, p.o.) the plasma levels of the -isomer were found to be approximately three times those of the -isomer. Using these deuterium labeled mixtures the disposition of the two isomers has been examined in the isolated perfused dog liver, in hepatocytes and isolated microsomes. The results indicate that the difference in plasma levels of the - and -isomers is not dependent upon stereospecific absorption or excretion but rather it is caused by metabolism of the -isomer at a faster rate than that of the -isomer. 相似文献
10.
Addition of -nitroanisole to a reaction mixture containing phenobarbital-pretreated rabbit liver microsomes brings about an increase the reoxidation rate of NADH-reduced cytochrome b5. Addition of partially purified cytochrome b5 to a solution containing microsomes results in a marked increase in both NADH- and NADPH-dependent O-demethylation of -nitroanisole. -Nitroanisole also increases the rate of NADH mediated cytochrome P-450 reduction. From these and other results described in the Discussion section, we confirm that electrons required for NADH-dependent O-demethylation of -nitroanisole is transfered from NADH to cytochrome P-450 via cytochrome b5 and that cytochrome P-450 is the enzyme which catalyzes -nitroanisole O-demethylation. 相似文献
11.
The optimal incubation temperature for assay of the melatonin-forming enzyme, hydroxyindole-O-methyl transferase (HIOMT), of the Japanese quail pineal, was determined to be 47° C. In adult quail, HIOMT activity was high in continuous light and in the light phase of , and was low in continuous darkness and in the dark phase of . Age of the bird and length of the lighting treatment seemed to be important factors in demonstrating this effect of light and darkness on HIOMT activity. 相似文献
12.
Alfred H. Merrill Kihachiro Horiike Donald B. McCormick 《Biochemical and biophysical research communications》1978,83(3):984-990
Pyridoxamine (pyridoxine) 5′-phosphate oxidase (EC 1.4.3.5) purified from rabbit liver is competitively inhibited by the reaction product, pyridoxal 5′-phosphate. The Ki, 3 μM, is considerably lower than the Km for either natural substrate (18 and 24 μM for pyridoxamine 5′-phosphate and 25 and 16 μM for pyridoxine 5′-phosphate in 0.2 M potassium phosphate at pH 8 and 7, respectively). The Ki determined using a 10% rabbit liver homogenate is the same as that for the pure enzyme; hence, product inhibition is probably not diminished significantly by other cellular components. Similar determinations for a 10% rat liver homogenate also show strong inhibition by pyridoxal 5′-phosphate. Since the reported liver content of free or loosely bound pyridoxal 5′-phosphate is greater than Ki, the oxidase in liver is probably associated with pyridoxal 5′-phosphate. These results also suggest that product inhibition of pyridoxamine-P oxidase may regulate the rate of pyridoxal 5′-phosphate formation. 相似文献
13.
Ray W. Fuller Betty W. Roush Susan K. Hemrick Harold D. Snoddy Bryan B. Molloy 《Life sciences》1978,22(16):1421-1427
Bicyclic analogs of benzylamine (with the α carbon connected by one or more methylene units to the ortho position of the benzene ring) inhibited rabbit adrenal norepinephrine N-methyltransferase (NMT) . Inhibition was greater when the second ring contained five carbons (1-aminoindan) than when it contained four, six, or seven carbons. Substitution of chlorines on the benzene ring further enhanced the inhibition by 1-aminoindan. The most active inhibitor, 4,5-dichloro- 1-aminoindan, showed competitive kinetics with ?-norepinephrine as the variable substrate, and the Ki for this compound as an inhibitor of adrenal NMT was 0.22 μM. 4,5-Dichloro-1-aminoindan significantly decreased epinephrine concentration in the adrenal glands of exercised rats, suggesting that it was effective in inhibiting NMT . 相似文献
14.
The effect of beta-naphthoflavone on rabbit liver protein synthesis, and on the induction of cytochrome P-450 LM4 mRNA 总被引:1,自引:0,他引:1
K L Nash J Y Chiang A W Steggles 《Biochemical and biophysical research communications》1981,100(3):1111-1117
A single injection of β-naphthoflavone dispersed in corn oil causes significant changes in rabbit liver polysome and polysomal poly(A+)mRNA driven protein synthesis. The changes occur between 6–18 hr and 30–36 hr after the injection. Our data indicate that the first effect is due to the β-naphthoflavone and the second effect is due to the oil vehicle. translation of rabbit liver polysomes obtained from treated rabbits followed by specific immunoprecipition and gel electrophoresis, showed that maximal levels of translatable cytochrome P-450 LM4 occurred 18–24 hr after β-naphthoflavone treatment. 相似文献
15.
William L. Dean Robert D. Gray 《Biochemical and biophysical research communications》1982,107(1):265-271
Sedimentation equilibrium and sedimentation velocity measurements were carried out on cytochrome P-450LM2 from phenobarbital-treated rabbit liver and on cytochrome P-450LM4 from 5,6-benzoflavone-treated rabbit liver in the presence of the nonionic detergent . P-450LM2 was monomeric with a molecular weight of 48,800 and a Stokes radius of 3.1 nm in 7 g/l detergent and P-450LM4 was monomeric with a molecular weight of 49,800 and a Stokes radius of 2.6 nm at 5 g/l detergent. Both particles were spherical in shape under these conditions. Neither cytochrome was irreversibly denatured at these detergent concentrations as indicated by the ability to form substantial amounts (>60%) of the CO adduct with an absorption maximum at 451 nm (P-450LM2) or 448 nm (P-450LM4) when diluted into detergent-free buffer containing CO and sodium dithionite. 相似文献
16.
The cytotoxic potential of rabbit peripheral blood monocytes and alveolar macrophages in antibody-dependent cellular cytotoxicity (ADCC) toward both erythrocyte (RBCox) and tumor cell (CEM T-lymphoblast) targets was examined. ADCC was measured in a 4-hr 51Cr-release assay. Alveolar macrophages were more efficient at killing the tumor cell targets (optimally sensitized with rabbit antisera) than monocytes at similar effector cell/target cell () ratios. Tumor cell targets sensitized with seven different antisera (anti-CEM) were lysed by alveolar macrophages but not by the monocytes. In marked contrast, the monocytes were more effective at lysing the sensitized erythrocyte target cells. The degree of cytolysis of RBCox and CEM was dependent on the ratio and the degree of sensitization of these target cells. It was demonstrated that the effector cell selectivity in ADCC was directly related to their ability or inability to bind the sensitized target cells as determined by Fc-receptor rosette formation. The transition from monocyte to macrophage may, therefore, have resulted in an alteration in the criteria necessary for Fc-receptor binding to antibody-sensitized target cells and subsequent ADCC. 相似文献
17.
M J Duchesne A A Attallah J B Lee 《Biochemical and biophysical research communications》1975,64(1):196-203
PGA1 was incubated with rabbit renal cortical homogenates containing HSA (0–4.5%). The ability of this tissue to readily metabolize PGA1 progressively decreased with increasing HSA levels in the incubates The rate of disappearance of 3H-PGA1 was twice as rapid in rats treated with salicylic acid (S. A.) in comparison to control animals; since only 30% of the injected radioactivity was bound to the plasma of the S.A. treated rats, as compared to 90% bound to control plasma, an association may exist between the degree of binding of 3H-PGA1 and its rate of clearance. The studies indicate that PGA1 interaction with HSA decreases its metabolism , and slows down its clearance , implicating HSA as a possible factor in prostaglandins metabolism . 相似文献
18.
The 0.5M KCl wash of rabbit reticulocyte ribosomes (I fraction) catalyzes the deacylation of Met-tRNAfMet. Upon DEAE-cellulose column chromatography, the deacylase activity elutes with the 0.1M KCl wash of the column (f1) and is well-resolved from the peptide chain initiation factors (1–3). The deacylase activity is specific for Met-tRNAfMet (retic., ). Other aminoacyl tRNAs tested including fMet-tRNAfMet (retic., ), Phe-tRNA (), Val-tRNA (retic.), and Arg-tRNA (retic.) are completely resistant to the action of the deacylase. In the presence of the peptide chain initiation factor (IF1) and GTP, retic. Met-tRNAfMet forms the initiation complex Met-tRNAfMet:IF1:GTP (2), and in this ternary complex Met-tRNAfMet is not degraded by the deacylase. Met-tRNAfMet binds to IF1 independent of GTP, and in this complex, this Met-tRNAfMet is degraded by the deacylase.Prior incubation of f1 with Met-tRNAfMet (retic.) strongly inhibited protein synthesis initiation, presumably due to deacylation of the initiator tRNA. This inhibition by f1 was completely prevented when Met-tRNAfMet (retic.) was pre-incubated with peptide chain initiation factors. 相似文献
19.
There are lysyl-ε-NH2 groups within about 3.5 Å distance across the intersubunit contact area of rabbit muscle phosphorylase , as shown by cross-linking with malonic diimidate. These include the lysines of N-terminal region as revealed by limited tryptic digestion, but the contribution of the tail lysines to overall formation of covalent dimers is small. The fine structure of dimer band on dodecylsulfate-gelelectrophoretograms of crosslinked phosphorylases suggests that the tail retains its freedom in the phosphorylase -AMP complex. Amidination induces the dissociation of phosphorylase dimer, which is slow relative to crosslinking. 相似文献
20.
Ian D. Smith Diana M. Temple Rodney P. Shearman 《Prostaglandins & other lipid mediators》1975,10(1):41-57
The anti-inflammatory analgesic drugs, aspirin, indomethacin, phenylbutazone, mefenamic acid, ibuprofen and flurbiprofen are shown to inhibit in a dose-dependent manner the force of contraction of isolated human pregnant myometrial strips which have been stimulated to contract by adding prostaglandin (PG) F2α to the tissue bath. These drugs and also flufenamic acid and salicin show a similar antagonism of the action of PGF2α with isolated rabbit non-pregnant myometrium. The ratio of the inhibitory concentration to the maximum plasma level after a normal dose suggests that phenylbutazone and possibly ibuprofen may be capable of inhibiting human uterine contractions . Patients who were treated with aspirin during induction of abortion using PGF2α during the second trimester of pregnancy showed no significant change in the induction-abortion interval compared with patients not taking aspirin. 相似文献