YC-1, a potent antithrombotic agent, induces lipolysis through the PKA pathway in rat visceral fat cells.
This study investigated the effects of 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), a soluble guanylyl cyclase (sGC) activator and potential antithrombotic agent, on lipolysis in isolated visceral fat cells of the rat. Visceral fat cells were isolated from epididymal fat pads of rats and treated with YC-1 at different doses and times. Glycerol release, and intracellular cAMP and cGMP levels were analyzed by specific kits. Moreover, several inhibitors or drugs were used to examine the signal transduction pathways of YC-1-induced lipolysis in adipocytes. Herein we report that YC-1 stimulated glycerol release in dose- and time-dependent manners. Intracellular cAMP and cGMP levels of adipocytes both increased in time-dependent manners, but elevation of the cGMP level was faster and higher than that of the cAMP level after YC-1 treatment. An sGC inhibitor (ODQ) inhibited YC-1-induced glycerol release, indicating the involvement of sGC in YC-1-induced lipolysis. Administration of insulin, an activator of type-3B phosphodiesterase (PDE-3B), attenuated YC-1-induced lipolysis, indicating that elevation of the cAMP level is an important step in the lipolytic effect of YC-1. In addition, YC-1-induced lipolysis was inhibited by a protein kinase A (PKA) inhibitor (KT5720) but not by a PKG inhibitor (KT5823), indicating that YC-1-induced lipolysis occurs through a PKA-dependent pathway. A Western blot analysis showed that extracellular signal-regulated kinase was not phosphorylated by YC-1 treatment. In conclusion, our results suggest that YC-1 might stimulate lipolysis via activation of sGC/cGMP and then activation of the cAMP/PKA signaling cascade in isolated rat visceral adipocytes.
Institute of Cardiovascular Medicine, Cathay General Hospital, Taipei 10630, Taiwan.
Chih-Hui
CH
Chin
Feng-Chou
FC
Tsai
Sy-Ping
SP
Chen
Ke-Chuan
KC
Wang
Chao-Chien
CC
Chang
Man-Hui
MH
Pai
Tsorng-Harn
TH
Fong
D017667:Adipocytes / Q000187:drug effects* / Q000201:enzymology; D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D007191:Indazoles / Q000494:pharmacology*; D050152:Intra-Abdominal Fat / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D008066:Lipolysis / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology
D005343:Fibrinolytic Agents; D007191:Indazoles; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D017868:Cyclic AMP-Dependent Protein Kinases