Hachimi-jio-gan (HJ) is a Chinese medicine that has been widely used for the treatment of
nephrotic syndromes,
hypertension, and
diabetes mellitus. We reported that HJ lowers plasma
glucose in type 1 diabetic rats. We investigated the effects of HJ on diabetic
hyperglycemia and insulin secretion in type 2 diabetic Goto-Kakizaki (GK) rats. Eight-week-old diabetic GK rats were given free access to pellets containing 1% HJ extract
powder for 14 weeks. HJ consumption increased the food intake and
body weight of these rats in comparison to control rats. HJ may control the
body weight loss observed in GK rats. HJ also reduced
hyperglycemia in diabetic GK rats, and it significantly increased insulin secretion in non-fasting GK rats over the experimental period. In oral
glucose tolerance tests, HJ significantly improved the
insulin response at 30 min and reduced the plasma
glucose level at 60 min after
glucose administration (p < 0.05). Ten weeks after administration, the plasma
leptin levels significantly increased in the HJ group rats. These results demonstrate that in diabetic GK rats, HJ decreased the level of postprandial
glucose via enhanced insulin secretion coupled with the regulation of food intake by
leptin.