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151.
Philip J. Lowry Hugh P. J. Bennett Colin McMartin Alexander P. Scott 《The Biochemical journal》1974,141(2):427-437
An adrenocorticotrophic hormone (ACTH) was isolated from extracts of the pars distalis of the pituitary of the dogfish Squalus acanthias by gel filtration and ion-exchange chromatography. It had 15% of the potency of human ACTH in promoting cortico-steroidogenesis in isolated rat adrenal cells. Sequence analysis revealed it to be a nonatria-contapeptide with the following primary structure: Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Met-Gly-Arg-Lys-Arg-Arg-Pro-Ile-Lys-Val-Tyr-Pro-Asn-Ser-Phe-Glu-Asp-Glu-Ser-Val-Glu-Asn-Met-Gly-Pro-Glu-Leu. The N-terminal tridecapeptide sequence was identical with the proposed structure of dogfish alpha-melanocyte-stimulating hormone (alpha-MSH). On comparison with human ACTH eleven amino acid differences were seen, nine of which are in the 20-39 region of the molecule which is not essential for the steroidogenic activity of ACTH. A peptide identical with the 18-39 portion of this new ACTH was similarly isolated from the neurointermediate lobe of the pituitary where considerable amounts of dogfish alpha-MSH were found. This supported our view that ACTH as well as having a distinct biological role of its own is also the precursor of alpha-MSH. 相似文献
152.
M. A. Blajchman R. C. Lowry J. E. Pettit Peter Stradling 《BMJ (Clinical research ed.)》1970,3(5713):24-26
A case is reported in which severe thrombocytopenia occurred during administration and readministration of rifampicin. The patient''s erythrocytes gave a positive direct antiglobulin test due to complement on the red cell surface; in the serum, complement-fixing antibodies were detected which were directed against the drug.Immunological studies showed antibodies, of both IgG and IgM type, capable of fixing complement to both normal and the patient''s platelets, but only in the presence of rifampicin. In addition the IgM type of antibody (but not the IgG) was capable of fixing complement to normal red cells; again only in the presence of the drug. 相似文献
153.
154.
—The levels of ATP, phosphocreatine, glucose, glucose-6-P., lactate, and glycogen have been measured in brains and spinal cords of lamprey larvae. Levels of glycogen in the brains were high, sometimes exceeding 100 m-moles of glycosyl units/kg wet weight. Isolated brains incubated in oxygenated saline exhibited the same levels of ATP and phosphocreatine as brains of intact animals. The level of glucose in tissue water of isolated brains approximated that found in the medium, except at low concentrations where the brains maintained levels of glucose many times that of the medium. It is demonstrated that under metabolic stress lamprey brains produce glucose by the breakdown of glycogen and the probable action of a glucose-6-phosphatase. The hypothesis is proposed that cells of the brain exchange glucose by this mechanism. 相似文献
155.
156.
Diversity of Metabolic Patterns in Human Brain Tumors: Enzymes of Energy Metabolism and Related Metabolites and Cofactors 总被引:5,自引:3,他引:2
Oliver H. Lowry Sosamma J. Berger Joyce G. Carter Maggie M.-Y. Chi Jill K. Manchester Joseph Knor Mary E. Pusateri 《Journal of neurochemistry》1983,41(4):994-1010
Biopsies from 15 human gliomas, five meningiomas, four Schwannomas, one medulloblastoma, and four normal brain areas were analyzed for 12 enzymes of energy metabolism and 12 related metabolites and cofactors. Samples, 0.01-0.25 microgram dry weight, were dissected from freeze-dried microtome sections to permit all the assays on a given specimen to be made, as far as possible, on nonnecrotic pure tumor tissue from the same region. Great diversity was found with regard to both enzyme activities and metabolite levels among individual tumors, but the following generalities can be made. Activities of hexokinase, phosphorylase, phosphofructokinase, glycerophosphate dehydrogenase, citrate synthase, and malate dehydrogenase levels were usually lower than in brain; glycogen synthase and glucose-6-phosphate dehydrogenase were usually higher; and the averages for pyruvate kinase, lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and beta-hydroxyacyl coenzyme A dehydrogenase were not greatly different from brain. Levels of eight of the 12 enzymes were distinctly lower among the Schwannomas than in the other two groups. Average levels of glucose-6-phosphate, lactate, pyruvate, and uridine diphosphoglucose were more than twice those of brain; 6-phosphogluconate and citrate were about 70% higher than in brain; glucose, glycogen, glycerol-1-phosphate, and malate averages ranged from 104% to 127% of brain; and fructose-1,6-bisphosphate and glucose-1,6-bisphosphate levels were on the average 50% and 70% those of brain, respectively. 相似文献
157.
P T Pullan V Clement-Jones R Corder P J Lowry G M Rees L H Rees G M Besser M M Macedo A Galvao-Teles 《BMJ (Clinical research ed.)》1980,280(6216):758-759
Immunoreactive methionine enkephalin and beta-endorphin were sought by serial dilution of tissue extracts and assay of chromatographic fractions in non-endocrine tumour tissue from three patients with the ectopic adrenocorticotrophin syndrome associated with carcinoid tumours and in normal lung tissue and thymic tissue from a patient with myasthenia gravis. In all cases serial dilution of extracts showed parellelism to standard radioimmunoassay curves. The two peptides were found in high concentration in the three tumours but were undetectable in the control tissues. In a single case tested the methionine enkephalin concentration in a vein draining the tumour was twice that in a peripheral vein. In view of their profound effect on behaviour in animals and potent analgesic activity in animals and man the ectopic secretion of methionine enkephalin and beta-endorphin may modify the clinical features of a wide variety of tumours and produce some of the diverse clinical syndromes associated with malignancy. 相似文献
158.
Cerebral carbohydrate metabolism during acute hypoxia and recovery 总被引:29,自引:20,他引:9
Abstract— The levels of ATP, ADP, AMP and phosphocreatine, of four amino acids, and of 11 intermediates of carbohydrate metabolism in mouse brain were determined after: (1) various degrees of hypoxia; (2) hypoxia combined with anaesthesia; and (3) recovery from severe hypoxia. Glycogen decreased and lactate rose markedly in hypoxia, but levels of ATP and phosphocreatine were normal or near normal even when convulsions and respiratory collapse appeared imminent. During 30 s of complete ischaemia (decapitation) the decline in cerebral ATP and phosphocreatine and the increase in AMP was less in mice previously rendered hypoxic than in control mice. From the changes we calculated that the metabolic rate had decreased by 15 per cent or more during 30 min of hypoxia. Hypoxia was also associated with decreases of cerebral 6-phosphogluconate and aspartate, and increases in alanine, γ-aminobutyrate, α-ketoglutarate, malate, pyruvate, and the lactate :pyruvate ratio. Following recovery in air (10 min), increases were observed in glucose (200 per cent), glucose-6-phosphate, phosphocreatine and citrate, and there was a fall in fructose-1, 6-diphosphale. Similar measurements were made in samples from cerebral cortex, cerebellum, midbrain and medulla. Severe hypoxia produced significant increases in lactate and decreases in glycogen in all areas; γ-aminobutyrate levels increased in cerebral cortex and brain stem, but not in cerebellum. No significant changes occurred in ATP and only in cerebral cortex was there a significant fall in phosphocreatine. Phosphocreatine, ATP and glycogen were determined by quantitative histochemical methods in four areas of medulla oblongata, including the physiological respiratory centre of the ventromedial portion. After hypoxia, ATP was unchanged throughout and the changes (decreases) in phosphocreatine and glycogen were principally confined to dorsal medulla, notably the lateral zone. Thus there is no evidence that respiratory failure is caused by a ‘power’ failure in the respiratory centre. It is suggested that in extremis a protective mechanism may cause neurons to cease firing before high-energy phosphate stores have been exhausted. 相似文献
159.
160.
An enzymatic cycling method for nicotinamide-adenine dinucleotide with malic and alcohol dehydrogenases 总被引:20,自引:0,他引:20
A method for measuring nicotinamide-adenine dinucleotide by enzymatic cycling is described which uses malic and alcohol dehydrogenases (EC 1.1.1.37, and EC 1.1.1.1) for the enzyme couple. After cycling, malate is measured with either malic dehydrogenase or malic enzyme (EC 1.1.1.40). The method has a number of advantages compared to those previously described. The cycling rate is high (greater than 30 000/hr); blank values are low; the reaction is linear over a wide range of NAD concentrations; and the terminal indicator reaction requires only one step. In addition the system is well suited for double cycling. This was shown by measurements of NAD in nuclei and cytoplasm from single dorsal root ganglion cells (rabbit). The overall amplification in this case was about 1 000 000. 相似文献