Effects of rhodiola-water extract on plasma glucose concentration and plasma β-endorphin level in STZ-diabetic rats. (A) The plasma glucose lowering activity produced by rhodiola-water extract through an intraperitoneal (i.p.) injection into STZ-diabetic rats. (B) Plasma β-endorphin-like immunoreactivity (BER) level in STZ-diabetic rats receiving i.p. injection of rhodiola-water extract. Values of mean and bar of S.E.M. were obtained from each group of 8 rats. Vehicle only (0.9% saline) was given at the same volume. **p < 0.01 and ***, p < 0.001 versus data from animals treated with vehicle (0).