Inhibitory effect of hypocrellin A on protein kinase C in liver and skeletal muscle of obese Zucker rats.
In this ex vivo study, the inhibitory activity of hypocrellin A (HA), a perylene quinonoid pigment isolated from the Chinese medicinal fungus Hypocrella bambuase, on protein kinase C (PKC) enzyme activity in insulin target tissues of obese Zucker rats was assessed. Pre-incubation with HA for 30 minutes significantly inhibited the activity of partially purified PKC enzyme from liver and soleus skeletal muscle in a dose-dependent manner (IC50 = 0.07 and 0.26 microg/ml, respectively). HA produced a greater inhibitory effect in enzyme prepared from the liver than enzyme prepared from soleus muscle. Since total PKC activity in these two insulin target tissues is the net result of several different isoforms of PKC, and PKC-theta is a major isoform expressed in the soleus skeletal muscle, the present data suggest that the naturally occurring compound, HA, may selectively inhibit certain PKC isoforms other than PKC-theta. Further investigations are required to determine which PKC isoforms are most susceptible to HA and whether changes in PKC signaling during treatment with HA can reverse abnormalities of glucose and lipid metabolism in insulin resistant and diabetic states.
Department of Health Sciences, University of Technology, Sydney, NSW, Australia. xianqin.qu@uts.edu.au
Xianqin
X
Qu
Lei
L
Dang
J Paul
JP
Seale
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D003920:Diabetes Mellitus / Q000378:metabolism*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D007333:Insulin Resistance; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000201:enzymology; D009765:Obesity; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology*; D019800:Phenol; D011493:Protein Kinase C / Q000378:metabolism*; D011809:Quinones / Q000494:pharmacology*; D051381:Rats; D011924:Rats, Zucker
D000970:Antineoplastic Agents; D004365:Drugs, Chinese Herbal; D011809:Quinones; D019800:Phenol; D010569:Perylene; D011493:Protein Kinase C; C048388:hypocrellin A