leptin has been researched along with arachidonyltrifluoromethane* in 2 studies
2 other study(ies) available for leptin and arachidonyltrifluoromethane
| Article | Year |
|---|---|
Leptin rapidly activates PPARs in C2C12 muscle cells.
Experimental evidence suggests that leptin operates on the tissues, including skeletal muscle, also by modulating gene expression. Using electrophoretic mobility shift assays, we have shown that physiological doses of leptin promptly increase the binding of C2C12 cell nuclear extracts to peroxisome proliferator-activated receptor (PPAR) response elements in oligonucleotide probes and that all three PPAR isoforms participate in DNA-binding complexes. We pre-treated C2C12 cells with AACOCF3, a specific inhibitor of cytosolic phospholipase A2 (cPLA2), an enzyme that supplies ligands to PPARs, and found that it abrogates leptin-induced PPAR DNA-binding activity. Leptin treatment significantly increased cPLA2 activity, evaluated as the release of [3H]arachidonic acid from pre-labelled C2C12 cells, as well as phosphorylation. Further, using MEK1 inhibitor PD-98059 we showed that leptin activates cPLA2 through ERK induction. These results support a direct effect of leptin on skeletal muscle cells, and suggest that the hormone may modulate muscle transcription also by precocious activation of PPARs through ERK-cPLA2 pathway. Topics: Animals; Arachidonic Acids; Cell Line; DNA; Enzyme Inhibitors; Flavonoids; Kinetics; Leptin; MAP Kinase Kinase 1; MAP Kinase Signaling System; Mice; Myoblasts, Skeletal; Peroxisome Proliferator-Activated Receptors; Phospholipases A; Phospholipases A2; Phosphorylation | 2005 |
Identifying pathways involved in leptin-dependent aggregation of human platelets.
To investigate the role of phospholipase C (PLC), phospholipase A(2) (PLA(2)), calcium, and protein kinase C (PKC) in mediating leptin-enhanced aggregation of human platelets.. In vitro, ex vivo study.. Outpatient's Service for Prevention and Treatment of Obesity at the University Hospital of Messina, Italy.. In total, 14 healthy normal-weight male (age 31.4+/-1.9 y; body mass index 22.7+/-0.6 kg/m2) subjects.. Adenosine diphosphate-(ADP-) induced platelet aggregation and platelet free calcium were measured after incubation of platelets with leptin alone (5-500 ng/ml), or leptin (50 and 100 ng/ml) in combination with anti-human leptin receptor long form antibody (anti-ObRb-Ab, 1:800-1:100 dilutions), PLC inhibitor U73122 (3.125-25 microM), PLA(2) inhibitor AACOCF3 (1.25-10 microM), or PKC inhibitor Ro31-8220 (1.25-10 microM).. Platelet stimulation with leptin leads to a significant and dose-dependent increase in ADP-induced platelet aggregation and platelet free calcium concentrations. Leptin effects on both platelet aggregation and calcium mobilization were completely abated by the co-incubation with leptin and anti-ObRb-Ab. Leptin-induced platelet aggregation was dose-dependently inhibited by U73122, AACOCF3, or Ro31-8220. The effect of leptin on intracellular calcium was inhibited in a dose-dependent manner by incubation with U73122 and AACOCF3, but not with Ro31-8220.. Our study confirms that leptin is able to enhance ADP-induced aggregation of human platelets, and raise the possibility that PLC, PKC, PLA(2), and calcium could play a relevant role in mediating the proaggregating action of leptin. Topics: Adenosine Diphosphate; Adult; Analysis of Variance; Antibodies, Monoclonal; Arachidonic Acids; Calcium; Estrenes; Humans; Indoles; Leptin; Male; Phospholipases A; Platelet Aggregation; Protein Kinase C; Pyrrolidinones; Signal Transduction; Type C Phospholipases | 2004 |