@misc{PueschelOppermannMuscholetal.1989, author = {P{\"u}schel, Gerhard Paul and Oppermann, Martin and Muschol, Waldemar and G{\"o}tze, Otto and Jungermann, Kurt}, title = {Increase of glucose and lactate output and decrease of flow by human anaphylatoxin C3a but not C5a in perfused rat liver}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16733}, year = {1989}, abstract = {The complement fragments C3a and C5a were purified from zymosan-activated human serum by column chromatographic procedures after the bulk of the proteins had been removed by acidic polyethylene glycol precipitation. In the isolated in situ perfused rat liver C3a increased glucose and lactate output and reduced flow. Its effects were enhanced in the presence of the carboxypeptidase inhibitor DL-mercaptomethyl-3-guanidinoethylthio-propanoic acid (MERGETPA) and abolished by preincubation of the anaphylatoxin with carboxypeptidase B or with Fab fragments of an anti-C3a monoclonal antibody. The C3a effects were partially inhibited by the thromboxane antagonist BM13505. C5a had no effect. It is concluded that locally but not systemically produced C3a may play an important role in the regulation of local metabolism and hemodynamics during inflammatory processes in the liver.}, language = {en} } @misc{PueschelNathJungermann1987, author = {P{\"u}schel, Gerhard Paul and Nath, Annegret and Jungermann, Kurt}, title = {Increase of urate formation by stimulation of sympathetic hepatic nerves, circulating noradrenaline and glucagon inthe perfused rat liver}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16728}, year = {1987}, abstract = {In the isolated rat liver perfused in situ stimulation of the nerve bundles around the portal vein and the hepatic artery caused an increase of urate formation that was inhibited by the α1-blocker prazosine and the xanthine oxidase inhibitor allopurinol. Moreover, nerve stimulation increased glucose and lactate output and decreased perfusion flow. Infusion of noradrenaline had similar effects. Compared to nerve stimulation infusion of glucagon led to a less pronounced increase of urate formation and a twice as large increase in glucose output but a decrease in lactate release without affecting the flow rate. Insulin had no effect on any of the parameters studied.}, language = {en} } @misc{PueschelHespelingOppermannetal.1993, author = {P{\"u}schel, Gerhard Paul and Hespeling, Ursula and Oppermann, Martin and Dieter, Peter}, title = {Increase in prostanoid formation in rat liver macrophages (Kupffer cells) by human anaphylatoxin C3a}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16716}, year = {1993}, abstract = {Human anaphylatoxin C3a increases glycogenolysis in perfused rat liver. This action is inhibited by prostanoid synthesis inhibitors and prostanoid antagonists. Because prostanoids but not anaphylatoxin C3a can increase glycogenolysis in hepatocytes, it has been proposed that prostanoid formation in nonparenchymal cells represents an important step in the C3a-dependent increase in hepatic glycogenolysis. This study shows that (a) human anaphylatoxin C3a (0.1 to 10 mug/ml) dose-dependently increased prostaglandin D2, thromboxane B, and prostaglandin F2alpha formation in rat liver macrophages (Kupffer cells); (b) the C3a-mediated increase in prostanoid formation was maximal after 2 min and showed tachyphylaxis; and (c) the C3a-elicited prostanoid formation could be inhibited specifically by preincubation of C3a with carboxypeptidase B to remove the essential C-terminal arginine or by preincubation of C3a with Fab fragments of a neutralizing monoclonal antibody. These data support the hypothesis that the C3a-dependent activation of hepatic glycogenolysis is mediated by way of a C3a-induced prostanoid production in Kupffer cells.}, language = {en} } @misc{HespelingJungermannPueschel1995, author = {Hespeling, Ursula and Jungermann, Kurt and P{\"u}schel, Gerhard Paul}, title = {Feedback-inhibition of glucagon-stimulated glycogenolysis in hepatocyte/kupffer cell cocultures by glucagon-elicited prostaglandin production in kupffer cells}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16697}, year = {1995}, abstract = {Prostaglandins, released from Kupffer cells, have been shown to mediate the increase in hepatic glycogenolysis by various stimuli such as zymosan, endotoxin, immune complexes, and anaphylotoxin C3a involving prostaglandin (PG) receptors coupled to phospholipase C via a G(0) protein. PGs also decreased glucagon-stimulated glycogenolysis in hepatocytes by a different signal chain involving PGE(2) receptors coupled to adenylate cyclase via a G(i) protein (EP(3) receptors). The source of the prostaglandins for this latter glucagon-antagonistic action is so far unknown. This study provides evidence that Kupffer cells may be one source: in Kupffer cells, maintained in primary culture for 72 hours, glucagon (0.1 to 10 nmol/ L) increased PGE(2), PGF(2 alpha), and PGD(2) synthesis rapidly and transiently. Maximal prostaglandin concentrations were reached after 5 minutes. Glucagon (1 nmol/L) elevated the cyclic adenosine monophosphate (cAMP) and inositol triphosphate (InsP(3)) levels in Kupffer cells about fivefold and twofold, respectively. The increase in glyco gen phosphorylase activity elicited by 1 nmol/L glucagon was about twice as large in monocultures of hepatocytes than in cocultures of hepatocytes and Kupffer cells with the same hepatocyte density. Treatment of cocultures with 500 mu mol/L acetylsalicylic acid (ASA) to irreversibly inhibit cyclooxygenase (PGH-synthase) 30 minutes before addition of glucagon abolished this difference. These data support the hypothesis that PGs produced by Kupffer cells in response to glucagon might participate in a feedback loop inhibiting glucagon-stimulated glycogenolysis in hepatocytes.}, language = {en} }