Conference Article| October 01 1981 Regulation of glycogen metabolism in isolated rabbit alveolar macrophages KREUSCH JÜRGEN; KREUSCH JÜRGEN 1Biochemisches Institut an der Medizinischen Fakultät, University of Freiburg, D 7800 Freiburg, Federal Republic of Germany Search for other works by this author on: This Site PubMed Google Scholar FRIEDRICH HOFMANN; FRIEDRICH HOFMANN 2Biochemisches Institut an der Medizinischen Fakultät, University of Freiburg, D 7800 Freiburg, Federal Republic of Germany Search for other works by this author on: This Site PubMed Google Scholar KARL DECKER KARL DECKER 3Biochemisches Institut an der Medizinischen Fakultät, University of Freiburg, D 7800 Freiburg, Federal Republic of Germany Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1981) 9 (5): 435. https://doi.org/10.1042/bst0090435 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation KREUSCH JÜRGEN, FRIEDRICH HOFMANN, KARL DECKER; Regulation of glycogen metabolism in isolated rabbit alveolar macrophages. Biochem Soc Trans 1 October 1981; 9 (5): 435. doi: https://doi.org/10.1042/bst0090435 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1981 Biochemical Society1981 Article PDF first page preview Close Modal You do not currently have access to this content.

Sinusoidal cells of rat liver, rat peritoneal macrophages and rabbit alveolar macrophages were checked for their viability and compared with regard to cell weight, protein and DNA content. Glycogen was virtually absent from sinusoidal cells and peritoneal macrophages; alveolar macrophages contained glycogen whose level increased after activation by Freund's adjuvant and decreased during phagocytosis in the absence of glucose. Of the different nucleotides assayed, UDPglucose levels were low in the nonglycogen-forming cells, but quite high in alveolar macrophages. The capacity to metabolize galactose is much smaller in all cell types investigated than in hepatocytes.

Activities of glucokinase and hexokinase were measured in whole liver, in isolated parenchymal cells and in sinusoidal cells from neonatal, suckling and weanling rats. Hexokinase activity was found to be high in fetal and newborn livers, decreased gradually and attained a plateau in 21 days. Glucokinase activity, on the other hand, was very low in fetal and newborn livers, but increased 40 fold in 21 days after birth. Measurement of the enzyme activities in isolated cells revealed a gradual increase in glucokinase activity in parenchymal cells and a parallel decrease of this enzyme in sinusoidal cells as a function of age. Hexokinase activity in parenchymal or sinusoidal cells did not change significantly at different stages of growth. The relative contribution by parenchymal cells to the liver glucokinase activity increased gradually during maturation whereas that by the sinusoidal cells decreased during this period. The evidence presented suggests that sinusoidal cells may be playing a vital role in the metabolic activities of liver in the early stages of postnatal development.

Isolated rat hepatocytes preserved for several hours their contents of ATP, CTP, GTP, UTP and UDPG. Leakage of intracellular and membrane-bound enzymes remained in the range observed with the isolated perfused rat liver. D-Galactosamine led to a rapid decrease of the UTP and UDPG contents while ATP and GTP levels remained unaffected. The sum of acid-soluble uracil nucleotides increased immediately after the addition of D-galactosamine, indicating release of the UTP-mediated feed-back inhibition of pyrimidine nucleotide de novo biosynthesis. Addition of uridine to a hepatocyte suspension resulted in a rapid increase in the levels of uridylate derivatives; the concentrations of UTP and UDPG, previously depleted by D-galactosamine, were restored within 1 h. Isolated hepatocytes appear suitable for studies on the pathogenic sequence of events elicited by D-galactosamine and on the regulation of pyrimidine biosynthesis.

Isolated Kupffer cells synthesize urea from a variety of added amino acids at a rate comparable to that of hepatocytes. Urea synthesis was determined both by enzymic product analysis and by the incorporation of labeled bicarbonate into urea. Studies on uptake of radioactive insulin showed that both hepatocytes and Kupffer cells bind insulin to almost the same extent. However, much higher degradation of insulin was found with Kupffer cells than with hepatocytes. Labeled insulin-anti-insulin serum (I-AIS) complex is neither bound nor taken up by hepatocytes. Kupffer cells, on the other hand, removed the complex in a time-dependent manner from the medium and partially degraded it.

The nucleoti-e contents of isolated rat Kupffer cells were found to be smaller than those of hepatocytes. The rate of UDPGal formation from D-galactose was much lower in Kupffer cells than in hepatocytes. The viability of the former was checked by measuring the leakage of enzymes and the formation of UTP from uridine. Addition of GalN to isolated Kupffer cells did not decrease their UTP and UDPG contents as much as those of hepatocytes. The same results were obtained when cells were isolated from GalN-pretreated animals. The incorporation of labeled amino acids into protein after GalN addition was much less reduced in Kupffer cells than in hepatocytes. The data suggest that Kupffer cells do not contribute to GalN-induced liver injury as a result of uridylate trapping.

Conference Article| December 01 1975 The Effect of d-Galactosamine and Uridine on the Uracil Nucleotide Contents of Isolated Rat Hepatocytes FRIEDRICH HOFMANN; FRIEDRICH HOFMANN 1Biochemisches Institut an der Medizinischen Fakultät der Universität Freiburg, D-7800 Freiburg, Hermann-Herder Strasse 7, West Germany Search for other works by this author on: This Site PubMed Google Scholar KARL DECKER KARL DECKER 1Biochemisches Institut an der Medizinischen Fakultät der Universität Freiburg, D-7800 Freiburg, Hermann-Herder Strasse 7, West Germany Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1975) 3 (6): 1084–1086. https://doi.org/10.1042/bst0031084 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation FRIEDRICH HOFMANN, KARL DECKER; The Effect of d-Galactosamine and Uridine on the Uracil Nucleotide Contents of Isolated Rat Hepatocytes. Biochem Soc Trans 1 December 1975; 3 (6): 1084–1086. doi: https://doi.org/10.1042/bst0031084 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search Keywords: EGTA, ethanedioxybis(ethy1amine)tetra-acetic acid This content is only available as a PDF. © 1975 Biochemical Society1975 Article PDF first page preview Close Modal You do not currently have access to this content.