TY  - GEN
A1  - Hespeling, Ursula
A1  - Jungermann, Kurt
A1  - Püschel, Gerhard Paul
T1  - Feedback-inhibition of glucagon-stimulated glycogenolysis in hepatocyte/kupffer cell cocultures by glucagon-elicited prostaglandin production in kupffer cells
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 036 
KW  - perfused-rat-liver
KW  - aggregated immunoglobulin-g
KW  - intercellular communication
KW  - adenylate-cyclase
KW  - arachidonic-acid
KW  - activation
KW  - glucose
Y1  - 1995
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16697
ER  - 
TY  - GEN
A1  - Püschel, Gerhard Paul
A1  - Hespeling, Ursula
A1  - Oppermann, Martin
A1  - Dieter, Peter
T1  - Increase in prostanoid formation in rat liver macrophages (Kupffer cells) by human anaphylatoxin C3a
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 037 
KW  - lactate output
KW  - glucose
KW  - complement
KW  - flow
KW  - prostaglandin-f2-alpha
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16716
ER  -