摘要:

AbstractIt has been established that inositol 1,4,5‐trisphosphate(IP3) is responsible for the mobilization of calcium(Ca2+) from intracellular locations in a wide variety of tissues, and that this response triggers the stimulation of several hormones and neurotransmitters. However, these phenomena have yet to be examined in the mammary epithelium.Ca2+uptake from the medium into the endoplasmic reticulum(ER) and Golgi apparatusin vitroin both pregnant and lactating mouse mammary epithelial cells was studied and a strong Ca2+release from these organelles into the medium with the use of IP3 was shown. The Ca2+uptake and its release due to IP3 was also usually greater during pregnancy than lactatio

ISSN:0263-6484    

DOI:10.1002/cbf.290080402

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of methotrexate (MTX) on the mitochondrial oxidation of cytosolic‐reducing equivalents in HeLa cells was studied. MTX inhibited (100 per cent) malate dehydrogenase activity, but no effect was observed on that of GOT. MTX (0.5 mM) inhibited (100 per cent) the activity of reconstituted enzymatic system MDH–GOT, probably as a consequence of inhibition of malate dehydrogenase activity. MTX decreased pyruvate production (54 per cent), demonstrating its inhibitory action on the malate‐aspartate shuttle. Blockage of the malate–aspartate shuttle by MTX accounts for the decrease in cellular energetic gain. The results obtained are consistent with the view that in HeLa cells, as well as in other tumour cells, the trasport of reducing equivalents from cytoplasmic NADH into the respiratory chain of mitochondria is via the malate‐aspartat

ISSN:0263-6484    

DOI:10.1002/cbf.290080403

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractOxygen consumption was depressed in mitochondria isolated from halothane sensitive pig (HP) muscle. The calculation of the respiratory control ratio (RCR) indicated that mitochondria were more affected at the site‐I level of the respiratory chain. Calcium accumulation in these mitochondria was not altered when driven by the oxidation of succinate. This process was abolished when linked to ATP as a source of energy. ATP transport was completely inhibited in (HP) mitochondri

ISSN:0263-6484    

DOI:10.1002/cbf.290080404

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of HUdR, proved to be anti‐metastaticin vivo, was studiedin vitroon cell proliferation, nucleoside uptake, membrane fluidity, expression of galactosylated glycans and proteoglycans in metastatic HM tumour cells. The observed increase in membrane fluidity and the suppression of nucleoside transport were early events of the HUdR action followed by decrease of galactosylated glycan and HSPG expression. However, these changes did not influence the proliferation capacity of the cells at the concentrations studied. As a consequence of the membrane alterations a reduced adhesiveness and spreading on extracellular matrix components was detected. In addition, the HUdR treated HM cells showed reduced capacity to invade fibroblast monolayersin vitro. Based on these observations, HUdR could be the prototype of new anti‐metastatic agents acting at the level of tumour–host intera

ISSN:0263-6484    

DOI:10.1002/cbf.290080405

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe immunological induction of arthritis in the knee of the rabbit is well established as a model for human rheumatoid arthritis. It has the special advantage of allowing the development of the condition, and the effect of disease‐modifying agents, to be followed.Attention has been focussed on the activity of glucose 6‐phosphate dehydrogenase in the synovial lining cells since the fourfold elevation of this activity was shown to be fundamental in the human condition. An equal elevation of this activity has now been demonstrated in the rabbit model. Furthermore, it has been shown that the oral administration of menadione decreases this activity towards normality with a concomitant decrease in the degree of inflammat

ISSN:0263-6484    

DOI:10.1002/cbf.290080406

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA method for the quantification of energy consuming processes described by Siemset al.6for reticulocytes and by Mülleret al.10for ascites tumour cells was applied to balance the ATP‐consumption of isolated rat hepatocytes. On the basis of decreased coupled respiration rates following the specific inhibition of energy‐requiring reactions, the energy demands of protein turnover, nucleic acid synthesis, Na+/K+‐ATPase and Ca2+‐transport of hepatocytes in different incubation media were assessed. These processes together with urea synthesis account for about 60 per cent of the total energy consumption in a glucose and amino acid‐enriched Eagle/Borsook medium. The metabolic flux rates of total ATP‐consumption and ATP‐consumption of single energy‐requiring processes in hepatocytes are compared with those in reticulocytes and different t

ISSN:0263-6484    

DOI:10.1002/cbf.290080407

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA cytochemical and electrophoretic analysis of alpha‐naphthyl and naphthol AS‐D acetate esterases from the radicles of pea seeds germinated for 24, 36 and 48 h permitted the detection of the loss of activity from the procortex with time after germination, but a stability of this activity in the prostele. Inhibitor studies showed the procambial enzyme as a single band of carboxylesterase activity the remainder being acetylesterase activity. The procambial carboxylesterase which is present in the more mature root apex corresponds to that of the 48‐h embryo (separating atRf

ISSN:0263-6484    

DOI:10.1002/cbf.290080408

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe presence of vanadate in primary cultures of rat hepatocytes produced a significant increase in the concentration of fructose 2,6‐bisphosphate and in the activity of 6‐phosphofructo 2‐kinase. Compared with insulin, vanadate had a more potent action on the metabolite increase, but a similar effect on the 6‐phosphofructo 2‐kinase activity. Both the insulin‐ and the vanadate‐dependent enhancements of 6‐phosphofructo 2‐kinase were inhibited by cycloheximide which specificially blocks protein synthesis on the translational level, suggesting that the increase of the enzyme activity was due to induction rather than to a change in the c

ISSN:0263-6484    

DOI:10.1002/cbf.290080409

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0263-6484    

DOI:10.1002/cbf.290080411

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0263-6484    

DOI:10.1002/cbf.290080413

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY