摘要:

Abstract:Optimal conditions for the synthesis ofo‐aminophenol andp‐nitrophenol glucuronides by a clonal strain of rat hepatoma cells (MH1C1) in culture were established. Properties of glucuronyltransferase (UDP‐glucuronate glucuronyltransferase (acceptor unspecific), E. C. 2.4.1.17) in homogenates of cultured hepatoma cells, subcutaneous tumours derived from these cells in rats, as well as livers of Buffalo rats were studied. In rat liver 83‐90 % and 92‐95 % of the glucuronyltransferase activity in homogenates top‐nitrophenol ando‐aminophenol respectively were latent, the latency being most pronounced in male animals. With homogenates of cultured hepatoma cells, on the other hand, digitonin activated 1.3 and 1.8‐fold only with p‐nitrophenol and o‐aminophenol as acceptors; other potential activators (Triton X‐100, UDP‐N‐acetylglucosamine and diethylnitrosamine) were either without effect or inhibited the enzyme. A 1.5‐2‐fold higher degree of activation of glucuronyltransferase was found in homogenates of hepatoma tumours derived from the same cells injected subcutaneously into Buffalo rats. The specific activity of fully activated glucuronyltransferase in homogenates of cultured hepatoma cells was, however, 2‐6.5‐fold higher than that of the fully activated rat liver enzyme. The rate ofp‐nitrophenol glucuronide synthesis by cultures of hepatoma cells increased up to a concentration of 0.10 mM of the aglycone in the growth medium. At concentrations of 0.3 mM and higher, a peculiar lag period was seen before any glucuronide appeared in the medium. This phenomenon was not seen witho‐aminophenol as acceptor and not in broken cell preparations with either substrate. The maximal rate ofo‐aminophenol glucuronidation in cultures of the hepatoma cells corresponded to that found for homogenates with 0.254.50 mM UDP‐glucuronate added to the incubation mixture. This value is in good agreement with the presumed intracellular levels of

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01519.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:The effects on mouse behaviour in the open field situation of controlled single doses of methyl mercury (MeHg) (1, 5, 10 mg Hg/kg) were investigated at varying times after intraperitoneal injection (1, 3, 72 hours). In an effort to correlate behavioural and biochemical data, the effects of dose and time after dose on the levels of selected glycolytic pathway intermediates, a‐glycerophosphate, adenine nucleotides and phosphocreatine were monitored. A very good correlation between brain biochemistry and behavioural effects of MeHg was observed. That is, the dose response relationship for the open field task correlated with alterations in levels of metabolic intermediates. At 1 and 3 hours after administration of MeHg, when the levels of the metabolic intermediates were significantly different from those of controls, altered behaviour was observed. At 72 hours post administration, when the biological parameters were approaching control values, a return to normal behaviour was observe

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01520.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Longitudinal strips from the antrum of rabbit stomachs were incubated for one hour in radioactive (42K) Krebs solution, and transferred to a constant flow apparatus where they were washed with non‐ radioactive solution. After an equilibration period of 28 min., the strips were exposed to 10−5M carbachol, or 10‐4M phenylephrine, noradrenaline, adrenaline, or isoprenaline. Some carbacholtreated strips were later also exposed to the adrenergic drugs. The mechanical responses and the effect of the drugs on42K‐efflux were studied. Carbachol which initiated rhythmic contractions or gave a “fused” (tetanic) contraction, produced a transient, statistically significant increase in K‐efflux as compared with untreated controls. Phenylephrine, noradrenaline, and adrenaline which had no effect or initiated rhythmic contractions in inactive strips, reduced the mechanical activity in strips previously exposed to carbachol. Isoprenaline had only inhibitory effects. All the four adrenergic drugs increased K‐efflux significantly in inactive strips, probably due to a‐receptor stimulation, since the effect of isoprenaline could be blocked by phentolamine. Noradrenaline also increased K‐efflux significantly in strips exposed to carbachol. The increase in K‐efflux produced by phenylephrine in the antrum strips was not as great as that previously recorded in fundus strips. The K‐uptake was the same, but K‐efflux was greater than in the fundus. It is concluded that a‐receptor stimulation increases K‐efflux regardless of whether the mechanical response is e

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01521.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Hyaluronic acid (HA)‐protein complex was extracted with 0.2 M‐NaCl from homogenized skin of the back of mice. The complex was separated from unrelated proteins by ethanol precipitation followed by three times chromatography on CM‐Sephadex columns. The composition of the complex isolated from mice treated with oestradiol differed significantly from the complex of the control mice, the ratio HA/protein was 3.5 times higher in the former than in the latter. The molecular sizes of the HA from the two samples were compared by means of gel filtration on Sepharose 2B column. Apart from a high molecular fraction containing 4 % of the HA from mice treated with oestradiol no difference was found between the elution patterns. The exchangeability of the chloride in the skin of control mice and mice treated with oestradiol was studied by means of the isotope dilution method. No significant difference was found between the two groups of

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb01522.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Sympathetic chain ganglia of newborn rats were cultured in Rose chambers with and without guanethidine. After one week, the cultures were examined by light microscopy for formaldehyde‐induced catecholamine fluorescence and by electron microscopy after fixation in 5% glutaraldehyde and 1% osmium tetroxide. Guanethidine sulphate (2 mg/l) caused an increase in the number of the small, intensely fluorescent (SIF) cells in the ganglion explants. Electron microscopic examination of guanethidine‐containing cultures revealed an increased number of small, granule‐containing (SGC) cells, which corresponded in size and shape to the SIF cells. Round vesicles (about 100 nm in diameter) and elongated vesicles (about 80 nm in cross section and about 200 nm in length) containing an electron‐dense core were observed in the cytoplasm of the SGC cells both in control and guanethidine‐containing cultures. The granular vesicles were most frequent in the periphery of the cytoplasm. In ganglia cultured with guanethidine, most SGC cells observed contained a greatly reduced number of granular vesicles as compared to SGC cells of the control

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb02008.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:The biliary excretion of intravenously administered35S‐ampicillin,35S‐azidocillin and35S‐benzyIpenicillin was studied in rats with ligated renal pedicles. The total excretion of radioactivity was of the same magnitude for the three penicillins (65‐72 % of the given doses) but the amounts of biologically active penicillin varied. Of the injected dose 44 % of biologically active ampicillin was excreted into the bile while the corresponding values for benzylpenicillin and azidocillin were 19% and 13%, respectively. Chromatographic studies indicated that as well as the unchanged drug, penicilloic acids of the corresponding penicillins were present in the bile. Incubation studies with rat liver slices showed that ampicillin was more stable to degradation than benzylpenicillin and azidocillin. It is suggested that the high hydrophobic character of the side chain of penicillins (high protein binding) may predispose to extensive biotransformation and lower amounts of unchanged penicillin in t

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb02009.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Abstract:Samples of plasma with the property of spontaneous activation of factor VII on incubation overnight at 0° were studied with regard to the concentration of prekallikrein, kininogen fractions, and the activity and concentration of proteinase inhibitors. A significantly higher concentration of prekallikrein was observed in the cold activation positive plasmas from pregnant and control subjects. The concentration of kininogen substrate 2, which was increased during pregnancy and treatment with oestrogenic oral contraceptives, was not correlated with the spontaneous cold activation. The rate of inhibition of kinino‐genase activity in normal plasma was very low at 0° as compared with that at 25°, and it is concluded that this may explain the odd temperature dependence of the spontaneous activation of factor

ISSN:0001-6683    

DOI:10.1111/j.1600-0773.1973.tb02010.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY