- Effect of Persistent Mild Hyperglycemic Hyperinsulinemia on Development of Insulin Resistance in Rats
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Yong Woon Kim, Jin Hyun Park, So Young Park, Jong Yeon Kim, Suck Kang Lee
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Yeungnam Univ J Med. 1995;12(2):269-281. Published online December 31, 1995
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DOI: https://doi.org/10.12701/yujm.1995.12.2.269
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Abstract
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- The effect of persistant mild hyperglycemic hyperinsulinemia on the development of the insulin resistance in rats was studied in vivo. Also, the characteristics of the insulin resistance compared with the insulin resistance of STZ diabetic rats. Persistant mild hyperglycemic hyperinsulinemic rat model was produced by ingestion of glucose polymer for 8 days. The glucose disappearance and infusion rate was measured by hyperinsulinemic euglycemic clamp to"Imique at steady state of blood glucose and insulin levels. The clamped level of blood glucose was 100 mg/dl, and the clamped levels of insulin were 70 pU/ml (physiologic condition) and 3000 pU/ml (supramaximal condition). Hepatic glucose producticon rate was calculated using measured data. And the glycogen synthetic capacity of skeletal muscle (soleus) and liver was measured after 2 hours of hyperinsulinemic euglycemic clamp study. The glucose disappearance and glucose infusion rate in glucose polymer group was decreased in the both physiological and supramaximal insulin level compared to the rate of the normal control group. The rate of STZ diabetic group was lowest at supramaximal insulin level among two another experimental groups. The hepatic glucose production rate of glucose polymer group was decreased compared to normal control but increased in STZ diabetic group. The glycogen synthetic capacity of skeletal muscle and liver of glucose polymer group was not significantly different from normal control group, but it was markedly decreased in STZ diabetic group. These results suggest that persistant mild hyperglycemic hyperinsulinemia may induce insulin resistance, but glycogen synthetic capacity is intact.
- Effects of insulin and exercise on glucose uptake of skeletal muscle in diabetic rats.
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Jin Hyun Park, Young Woon Kim, Jong Yeon Kim, Suck Kang Lee
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Yeungnam Univ J Med. 1990;7(1):29-37. Published online June 30, 1990
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DOI: https://doi.org/10.12701/yujm.1990.7.1.29
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Abstract
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- The effects of insulin and exercise on glucose uptake of skeletal muscle were investigated in soleus muscle isolated from low dose streptozotocin induced diabetic rat in vitro. Glucose uptake was assessed by measuring ³H-methylglucose uptake in vitro. Basal glucose uptake in diabetes was reduced by approximately one-third of the control value (5.6±0.73µMol/g/20min. in diabetes versus 8.4±0.77 in control, P<0.01). There was also a significant decrease (P<0.01) in glucose uptake of diabetes at physiologic insulin concentration (200 µIU/ml) by 40% (6.1±1.20 versus 10.0±0.81). Furthermore, maximal insulin (20000 µIU/ml)-stimulated glucose uptake was 36% lower in diabetes as compared with control (7.3±1.29 versus 11.4±1.29, P<0.01). In contrast, exercise (1.0 km/hr, treadmill running for 45 min.) effect on glucose uptake was so dramatic in diabetes that glucose uptake at basal state was 8.+1.09 and insulin stimulated-glucose uptake were 10.2±1.47 and 11.9±1.64, in 200 and 20000 µIU/ml added insulin, respectively. These results suggest that insulin insensitivity develops in skeletal muscle after 2 weeks of streptozotocin-induced diabetes, but these insensitivity was recovered significantly by single session of running exercise.
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