Inhibitory effect of hypocrellin A on protein kinase C in liver and skeletal muscle of obese Zucker rats
- Publication Type:
- Journal Article
- American Journal of Chinese Medicine, 2003, 31 (6), pp. 871 - 878
- Issue Date:
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 μg/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-0 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-θ. 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. © 2003 World Scientific Publishing Company & Institute for Advanced Research in Asian Science and Medicine.
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