• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.144-148
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• 1997

Insulin secretory response to various calcium concentrations was investigated in 10- to 12-week old male lean and obese Zucker rats using an in vitro pancreatic perfusion procedure. There was no significant difference in insulin secretion response to low, medium, and high calcium concentrations in the lean rat. However, the obese rat shows a characteristics of hypersecretion of insulin. The obese rat pancreas perfused with the low calcium concentration released as low insulin as the lean rat. When perfused with the medium calcium concentration, th obese rat pancreas released twice as much insulin as the lean rat. eh hypersecretory phenomenon was also seen in the obese rat pancreas perfused with the high calcium concentration during the first phase of erfusion period, but his phenomenon was gradually diminished during he second phase of perfusion period. These results indicate that there may be a selective insulin secretory response to the extracellular calcium in he obese Zucker rat pancreas.

• Biomedical Science Letters
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• v.15 no.4
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• pp.281-286
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• 2009

We found previously that Undaria pinnatifida extract has an effect of lowering blood glucose levels in diabetic rats. Therefore, an effect of Undaria pinnatifida extract on the insulin secretion directly from the pancreas was examined in this study. Neonatal diabetes were induced by intraperitoneal injection of Streptozotocin (100 mg/kg body weight) at age of day 1. Rats were fed a rodent pellet diet until they were grown to adults (age of 7 weeks). Rats having a fasting serum glucose level over 250 mg/dL were used in this feeding study and they were divided into two diet groups as follows; a diet with Undaria pinnatifida extract (5%) and a diet without this extract (control group). Fasting (12 hr) blood glucose and serum insulin levels were measured before and after feeding a diet with Undaria pinnatifida extract for 4 weeks. At the last day of feeding, in vitro pancreas perfusion was performed. Pancreas was stimulated with a perfusate without glucose during a period of 0~10 minutes and with a perfusate containing 200 mg/dL glucose during a period of 11~40 minutes. Insulin amount was measured using a radioimmuno assay. In results, amount of the insulin secreted from the pancreas in the diabetic rats fed Undaria pinnatifida extract was significantly greater than that in the diabetic control group during the periods of the equilibration period (0~10 min) and the first phase (11~20 min) of the insulin secretion (P<0.05). It is concluded that Undaria pinnatifida extract increases insulin secretion from the pancreas in the neonatal diabetic rats. Therefore, the blood glucose lowering effect of the Undaria pinnatifida extract may be elucidated by mechanisms with promoted insulin secretion from the pancreas in diabetic rats.

• Nutritional Sciences
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• v.8 no.2
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• pp.83-88
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• 2005

This study was to investigate the effect of psyllium seed husk (PSYL) on postprandial glucose control and insulin secretion dynamics in Sprague-Dawley rats. In experiment 1, the rise in postprandial serum glucose was monitored during a 240-min period using a maltose loading test In normal rats given 16.6 mg/l00 g B.W./ml of PSYL orally, all the blood glucose levels during the 240-min period did not show statistically significant differences from the corresponding levels in normal rats given water. However, in streptozotocin-induced diabetic rats given the same amount of PSYL, the blood glucose level at 30 min was significantly lower than that in diabetic rats given water, and the peak time of the rise in the postprandial glucose was delayed In experiment 2, the normal (N) and diabetic (Db) rats were given PSYL (25 mg/l00 g B.W./ml/day) orally for 5 days. Blood samples were collected in order to measure the s-glucose and s-insulin levels. The final s-glucose level at day 5 in Db-PSYL was significantly lower than that in the corresponding control rats (Db-CONT) and the final s-insulin level in Db-PSYL was significantly greater than that in Db-CONT. In vitro 40-min pancreas perfusion was performed at day 5 in order to examine the insulin secretion dynamics. Results showed that the amounts of insulin secreted during the first phase (11-20 min) and the second phase (21-40 min) in the Db-PSYL were significantly greater than those in Db-CONT. Therefore, it is concluded that psyllium seed husk could be beneficial for controlling postprandial glucose levels in the stretozotocin-induced diabetic rats, and it may be partially mediated by insulin secretion dynamics.