Ginseng Research Today is a free monthly online journal that collates and summarizes the latest research about Ginseng, including details on american ginseng, panax, benefits, side effects.

Mediation of beta-Endorphin by Ginsenoside Rh2 to Lower Plasma Glucose in Streptozotocin-Induced Diabetic Rats.

Lai DM, Tu YK, Liu IM, Chen PF, Cheng JT

Neurosurgical Division, Department of Surgery, National Taiwan University Hospital, Taipei City, Taiwan, R.O.C.

We investigated the plasma glucose-lowering mechanism(s) of Rh2, a ginsenoside derived from Panax ginseng, in rats with streptozotocin-induced diabetes (STZ-diabetic rats). After intravenous injection over 120 min into fasting STZ-diabetic rats, Rh2 decreased plasma glucose in a dose-dependent manner. In parallel to the lowering of plasma glucose, an increase of plasma beta-endorphin-like immunoreactivity was observed. In addition, naloxone and naloxonazine at doses sufficient to block opioid mu-receptors inhibited the plasma glucose-lowering action of Rh2 in genetically wild-type, diabetic mice. In contrast, Rh2 failed to lower plasma glucose in opioid mu-receptor knockout diabetic mice. An increase in gene expression at both the mRNA and protein levels of glucose transporter subtype 4 (GLUT 4) was observed in soleus muscle obtained from STZ-diabetic rats treated with Rh2 three times daily for one day; this increase in expression was absent when opioid mu-receptors were blocked. In conclusion, our results suggest that ginsenoside Rh2 may lower plasma glucose in STZ-diabetic rats based on an increase in beta-endorphin secretion that activates opioid mu-receptors thereby resulting in an increased expression of GLUT 4.

Published 1 February 2006 in Planta Med, 72(1): 9-13.
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