摘要:

AbstractThe relation between the effects of glucagon on oxygen consumption and glycolysis in livers from rats under different metabolic conditions was examined. Respiration of substrate‐free perfused livers with different glycolytic fluxes, induced by changes in the pattern of food intake, responds differently to the infusion of 1 nMglucagon. The increases in oxygen uptake caused by 1 nM glucagon correlate reasonably well with the absolute decreases in glycolysis. The degree of inhibition of glycolysis is approximately constant (58 per cent) for all metabolic conditions. When no recovery of glycolysis occurs upon cessation of glucagon infusion, the same happens with oxygen consumption, which remains stimulated. It is concluded that in livers with no appreciable biosynthetic activities, the action of glucagon on respiration and glycolysis may be interpreted in terms of an interaction of ‘cytosolic’ and mitochondrial ATP generating proc

ISSN:0263-6484    

DOI:10.1002/cbf.290060402

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractEpidermal growth factor receptors (EGF‐R) were measured in adult male and female mouse primary hepatocyte cultures. On culture day 1, female hepatocytes had significantly fewer EGF‐R than male hepatocytes (1·3 × 104versus 6·2 × 105per cell). Over the next three days, morphological changes consistent with progressive heptocyte dedifferentiation were observed. During this period, EGF‐R numbers progressively increased in female cultures and decreased in male cultures, and by day 4 the sexual difference in EGF‐R numbers was obliterated. These results indicate that a relationship exists between the degree of differentiation in hepatocyte cultures and the expression of EGF‐R on the

ISSN:0263-6484    

DOI:10.1002/cbf.290060403

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractIn order to gain morphological insights about the cell density dependency, hepatocytes cultured at a low cell density (about 1 × 105nuclei (cm2)−1) were examined ultrastructurally 24 h after plating (just prior to the beginning of DNA synthesis). The results were as follows: (i) glycogen rosettes disappeared completely in low density culture as compared with sections from an intact liver. In contrast, glycogen rosettes were still present in high density culture. (ii) Polysomes seemed increased in low density culture in comparison with those seen in sections from an intact liver and from the high density culture. (iii) In low density culture, the shape of mitochondria deviated from that of hepatocytes in an intact liver and the mitochondria often lost a characteristic close contact with rough endoplasmic reticulum (rough ER). (iv) In low density culture, bundles of filamentous structure were detected, which were not found in an intact liver or high density culture. The following features were found only in high density culture; (v) numberous villous cytoplasmic protrusions developed along the area facing adjacent cells, and seemed to intertwine with each other, and (vi) between the hepatocytes, only abortive junctions were found. These results indicate that the hepatocytes cultured at a low density express most of the characteristics of the hepatocytes in a regenerating liver and the features of the cells cultured at a high density are very similar to those of the hepatocytes in sections from an intact

ISSN:0263-6484    

DOI:10.1002/cbf.290060404

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe metabolism of the toxic lipid peroxidation product 4‐hydroxynonenal was investigated in the well‐differentiated rat heptoma cell line MH1C1.When exposed to 0·1 mM4‐hydroxynonenal (HNE), MH1C1cells consumed it in a time‐dependent manner. There was a linear relationship between the amount of aldehyde consumed and cell number in the range 0·5–4 × 106cells ml−1. This process was unaffected by pyrazole, suggesting that alcohol dehydrogenase is not involved.The whole homogenate of MH1C1cells consumed added HNE at a rate similar to that in intact cells. Fractionation of the homogenate showed that the highest HNE‐metabolizing activity is in the cytosol. The dialysed cytosol had almost no capacity to metabolize HNE, but this was restored by supplementation with NAD, NADH, NADP and NADPH.The metabolism of HNE in MH1C1cells is thus different from that in hepatocytes, which were shown to utilize cytosolic alcohol dehydrogenase for this process. Both reductive and oxidative pathways could be implicated in the metabolic activity of MH1C1cells towards HNE as well as bindin

ISSN:0263-6484    

DOI:10.1002/cbf.290060405

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractUsing reversed‐phase high‐performance liquid chromatography purine nucleotides, nucleosides and nucleobases as well as pyridine nucleotides were determined in extracts of reticulocytes and mature red blood cells of rabbits. The concentrations of almost all compounds measured decrease during the last phase of red blood cell maturation.These changes were interpreted with respect to the loss of mitochondria, accompanied by shifting the energy production from the preferentially oxidative mode to the exclusively glycolytic one and variations in the concentrations of purine compounds in blood plasma during reticulocyto

ISSN:0263-6484    

DOI:10.1002/cbf.290060406

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractMembrane fluidity of red blood cells drawn from malignant hyperthermic pigs and humans was studied using spin‐probes and electron paramagnetic resonance technique. The order parameter and rotational correlation time were determined with 12–doxylstearate and 16‐doxylstearate, respectively. It was found that halothane decreased both parameters, but that the decrease of these parameters in subjects susceptible to malignant hyperthermia was much greater than that in normal subjects. The differences were most pronounced at 3 mM halothane. A possibility of using blood for a non‐invasive screening for malignant hyperthermia is di

ISSN:0263-6484    

DOI:10.1002/cbf.290060407

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractHighly efficient methods for isolating two hydrolytic granules of neutrophils are described. Neutrophil obtained from guinea pig peritoneal exudate cells were washed extensively with isotonic sucrose and then treated with heparin. More than 95 per cent of the cells so treated were disrupted with a Dounce homogenizer. Since nuclei were broken, leaving other organelles intact, homogenates were incubated with DNase to reduce viscosity. Postnuclear supernatants were centrifuged on a discontinuous gradient of Percoll. Azurophil granules, high in β‐glucuronidase activity, sedimented at fractions ofd= 1·081 and showed very little activity of other marker enzymes. High neutral α‐glucosidase activity was observed in granular fractions ofd= 1·038 and it is suggested that this is a marker for specific granules of neut

ISSN:0263-6484    

DOI:10.1002/cbf.290060408

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe importance of γ‐glutamyl transpeptidase, the key enzyme of the γ‐glutamyl cycle and of thiols for the uptake of amino acids into rat pancreatic islets was investigated. Both serine–borate, an inhibitor of γ‐glutamy transpeptidase, and serine which does not inhibit this enzyme, but probabaly is a competitive inhibitor of amino acid uptake, inhibited of glutamine. The inhibitory effect of serine‐borate was not greater than that of serine alone. The uptake of glutamine was not affected by either GSH (reduced glutathione) or diamide (a thiol oxidant). Niether substances affected the uptake of leucine. The results indicate that the uptake of glutamine by rat pancreatic islets is not dependent on the functioning of γ‐glutamyl transpeptidase and that thiols are not important for the uptake of the amino acids glutam

ISSN:0263-6484    

DOI:10.1002/cbf.290060409

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractUsing benzo(a)pyrene (BaP) as a probe for aryl hydrocarbon hydroxylase (AHH) activity, differences in mixed‐function oxidase (MFO) activity were observed using microspectrofluorimetry in single living cells during long term treatment with 3‐methylcholanthrene (3‐MC) or carbaryl. Although these two compounds differ in chemical structure, similar effects were observed in 3T3 cell populations.The results suggest that the two compounds activate the same enzymatic system and that individual cells of a supposed homogeneous cell population are not equally sensitive to xenobiotics, i.e. subpopulations were observed which have differences in AHH act

ISSN:0263-6484    

DOI:10.1002/cbf.290060410

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractSpecific binding sites for angiotensin II in aorta and renal arteries have been studied in rat fetuses (18th day of pregnancy) and 1‐day‐old newborn rats by binding studies in arterial membranes using [125I] ileu‐5‐angiotensin II. One type of angiotensin receptor was found both in fetuses and in the newborns; the capacity of this (RT) decreased immediately after birth (from 0·06 ± 0·01 nMto 0·02 ± 0·005 nM; ± SEM) and the affinity (Kd) increased at birth (from 3·5 ± 0·6 nMto 19·5 ± 1·2 nM; ± SEM). Localization of the specific binding sites was studied by autoradiography on arteries from fetal and newborn rats either perfused with iodinated angiotensin II by cannulation of the aorta orin vitroon cryostat sections incubated with the radioactive angiotensin II. Both in fetuses and in the newborn the binding sites were located in the tunica

ISSN:0263-6484    

DOI:10.1002/cbf.290060411

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY