Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Noradrenaline-storing granules, a mitochondrial fraction and a microsomal fraction of bovine splenic nerve trunks were prepared by differential centrifugation. These particulate fractions were characterized by their noradrenaline content, succinate dehydrogenase and glucose-6-phosphatase activity. In the presence of ATP-Mg2+ all three fractions accumulated 45Ca2+ during incubation with 0.1 mM 45 CaCl2, buffered with potassium phosphate or glycylglycine (pH 7.5; 28 degrees C). The accumulated 45 Ca2+ was not removable by EGTA, and the uptake was absent at 0 degrees C or after destruction of the particles by sonication. The behaviour of the 45 Ca2+ -uptake into all three fractions against varying ATP-concentrations, metabolic inhibitors (pentachlorophenol, desaspidine, 2,4-dinitrophenol, N-ethylmaleimide, p-chloromercuribenzoate, sodium azide, amobarbital) and drugs (phenoxybenzamine, verapamil, prenylamine, reserpine, bretylium, phentolamine) was studied. Under nearly all conditions there were differences between the 45 Ca2+ -uptake into mitochondria and that into microsomes, which suggests two distinct uptake processes. The 45 Ca2+ -uptake into the granule fraction behaved intermediate between the two other fractions under many conditions, but not under all. Therefore, it is not possible to explain the 45 Ca2+ -uptake into the granule fraction as being due to contamination with mitochondria and microsomes; an inherent ATP-Mg2+ -dependent 45Ca2+ -uptake into the nerve granules must be postulated, which is not directly coupled with the noradrenaline transport into these particles. A particulate fraction (14000-100000 g), containing noradrenaline granules, was prepared from the vas deferens of the rat. Incubation with 5 X 10(-6) M (-)-noradrenaline and 0.1 mM 45Ca2+ showed that the particles of this fraction take up noradrenaline and 45Ca2+. The uptake of both was dependent on ATP-Mg2+. The ATP-Mg2+ -dependent uptake of both noradrenaline and 45Ca2+ was substantially reduced in the corresponding tissue fraction prepared from denervated vasa deferentia.
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PMID:Ca2+ -uptake into noradrenaline-storing granules of bovine splenic nerves. 18 27

Adult rat parenchymal hepatocytes in primary culture can be induced to enter into DNA synthesis and mitosis. The optimal conditions for hepatocyte replication are low plating density (less than 10,000 cells/sq cm) and 50% serum from two-thirds partially hepatectomized rats (48 hr after hepatectomy). Approximately 80% of the hepatocytes enter the cell cycle, and most of these cells go through mitosis. The replicating hepatocytes remain positive for glucose-6-phosphatase and negative for gamma-glutamyl transpeptidase, and they accumulate fat, in analogy to regenerating liver. Most of the replicating hepatocytes enter into multiple consecutive rounds of DNA synthesis. Dose-response studies between control animal serum and hepatocyte labeling index indicate that in unoperated animals the serum contains substances stimulatory as well as inhibitory for hepatic growth, with the inhibitory effect prevailing at high concentrations. After partial hepatectomy, the inhibitory activity disappears whereas the hepatopoietin activity reaches almost 90% of maximal biological effectiveness at 25% serum concentration. Addition of hormones to the system shows that the hepatopoietin activity is not identical to epidermal growth factor, platelet-derived growth factor, thyroxine, glucagon, or hydrocortisone. Norepinephrine abolishes the difference between control and hepatectomized serum but does not restore hepatopoietin activity when added to heat-inactivated serum. The results show that this system of replicating hepatocytes can be used to investigate the trophic factors that control growth of normal and neoplastic hepatocytes.
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PMID:Liver regeneration studies with rat hepatocytes in primary culture. 621 20