Journal of Yeungnam Medical Science

Original Articles

Effect of Age on Glucose Metabolism of Skeletal Muscle in Rats.: Eung Chan Jang, Woon Ki Youn, Suck Kang Lee; Yeungnam Univ J Med. 2001;18(1):94-100. Published online June 30, 2001; DOI: https://doi.org/10.12701/yujm.2001.18.1.94

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BACKGROUND
It is doubtful that aging causes deteriorated glucose metabolism and insulin resistance of skeletal muscle. Some researchers had different results about it. So we have studied the mechanism responsible for the abnormal glucose tolerance associated with aging in rapidly growing and matured rats. MATERIALS AND METHODS: Animals were used S.D. rats. Growing rats were 7 weeks old (BW: 160-190 gm) and matured rats were 28 weeks old (BW: 420-525 gm). RESULTS: Fasting blood glucose and plasma insulin levels were significantly elevated in matured rat compared with growing rats. And during oral glucose tolerance test the glucose level was also significantly elevated in matured rats. These results confirmed an insulin resistant state of aging. Insulin levels at 30 minutes of oral glucose tolerance test was significantly elevated in growing rat. But at 120 minutes it was maintained at higher level in matured rats than in growing rats. It suggested the possibility of increased insulin secretion by initial stimulation of beta-cells in growing rats, and increased secretion and decreased catabolic rate of insulin in matured rats. Glucose uptake rate of soleus muscle in matured rats was lower than that of growing rats, but the difference was not statistically significant. The dose(insulin)- responsive (glucose uptake) curve of soleus muscle was only slightly deviated to the right side. CONCLUSION: Glucose metabolism of rat skeletal muscle was worsened by aging. The data of glucose uptake experiments suggested the possibility of insulin resistance of skeletal muscle in matured rats, but the mechanism of insulin resistance of skeletal muscle need further studies.

Citations

Citations to this article as recorded by

Anti-Oxidative Effect of Jeokbaekhaogwanjoong-tang Distillate on Spleen Cells of Aged Rats
Young-Chun Park, Il-Gu Kim, Tae-Min Kim
The Korea Journal of Herbology.2016; 31(4): 35. CrossRef
The Effect of Jeokbaekhaogwanjung-tang Herbal Acupuncture Solution on the Immune Activity of Spleen Cells of Aged Rats
Hyun-Suk Lee, Kang-Min Choi, Yun-Kyoung Yim
Journal of Korean Medicine.2016; 37(1): 90. CrossRef
The Effect of Yongyukjowitang Distillate on the Immune Activity of Spleen Cells of Aged Rats
Jin-Wook Yi, Moon-Hee Jang, Jae-Song Choi, Taek-Won Ahn
Journal of Sasang Constitutional Medicine.2013; 25(3): 218. CrossRef

Effect of Acutely Increased Glucose Uptake on Insurin Sensitivity in Rats.: Yong Woon Kim, Youl In Ma, Suck Kang Lee; Yeungnam Univ J Med. 1997;14(1):53-66. Published online June 30, 1997; DOI: https://doi.org/10.12701/yujm.1997.14.1.53

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Abstract PDF: Insulin resistance is a prominent feature of diabetic state and has heterogeneous nature. However, the pathogenetic sequence of events leading to the emergence of the defect in insulin action remains controversial. It is well-known that prolonged hyperglycemia and hyperinsulinemia are one of the causes of development of insulin resistance, but both hyperglycemia and hyperinsulinemia stimulate glucose uptake in peripheral tissue. Therefore, it is hypothesized that insulin resistance may be generated by a kind of protective mechanism preventing cellular hypertrophy. In this study, to evaluate whether the acutely increased glucose uptake inhibits further glucose transport stimulated by insulin, insulin sensitivity was measured after preloaded glucose infusion for 2 hours at various conditions in rats. And also, to evaluate the mechanism of decreased insulin sensitivity, insulin receptor binding affinity and glucose transporter 4 (GLUT4) protein of plasma membrane of gastrocnemius muscle were assayed after hyperinsulinemic euglycemic clamp studies. Experimental animals were divided into five groups according to conditions of preloaded glucose infusion: group I, basal insulin (14+/-1.9 micronU/ml) and basal glucose (75+/-0.7 mg/dl), by normal saline infusion; group II, normal insulin (33+/-3.8 micronU/ml) and hyperglycemia (207+/-6.3 mg/dl), by somatostatin and glucose infusion; group III, hyperinsulinemia (134+/-34.8 micronU/ml) and hyperglycemia (204+/-4.6 mg/dl), by glucose infusion; IV, supramaximal insulin (100+/-2.2 mg/dl), by insulin and glucose infusion; group V, supramaximal insulin(4813+/-687.9 micronU/ml) and hyperglycemia (233+/-3.1 mg/dl), by insulin and glucose infusion. Insulin sensitivity was assessed with hyperinsulinemic euglycemic clamp technique. The amounts of preloaded glucose infusion(gm/kg) were 1.88+/-0.151 in group II, 2.69+/-0.239 in group III, 3.54+/-0.198 in groupIV, and 4.32+/-0.621 in group V. Disappearance rates of glucose (Rd, mg/kg/min) at steady state of hyperinsulinemic euglycemic clamp studies were 16.9+/-3.88 in group I, 13.5+/-1.05 in group II, 11.2+/-1.17 in group III, 13.2+/-2.05 in group IV, and 10.4+/-1.01 in group V. A negative correlation was observed between amount of preloaded glucose and Rd )r=-0.701, p<0.001) when all studies were combined. Insulin receptor binding affinity and content of GLUT4 were not significantly different in all experimental groups. These results suggest that increased glucose uptake may inhibit further glucose transport and lead to decreased insulin sensitivity.

The effect of regular physical exercise on glucose uptake in soleus and intravenous glucose tolerance in streptozotocin diabetic rats.: Myung Heup Chun, Yong Woon Kim, Jong Yeon Kim, Young Man Lee, Suck Kang Lee; Yeungnam Univ J Med. 1992;9(1):121-129. Published online June 30, 1992; DOI: https://doi.org/10.12701/yujm.1992.9.1.121

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Abstract PDF: The effect of exercise on plasma insulin, free fatty acid, and glucose uptake and glycogen concentration in soleus, and intravenous glucose tolerance of streptozotocin treated, diabetic Sprague-Dawley rats were studied. Diabetic-trained animals were subjected to a regular program of treadmill running for 4 weeks. Seventy-two hours after the last training session, basal and insulin-stimulated glucose uptake was studied in incubated strips (about 20 mg) of soleus muscle in vitro. Glucose tolerance was measured with intravenous infusion of 0.5 g glucose/kg body weight. In diabetic rats, training was associated with increase glucose uptake in basal and maximal insulin concentrations, decreased fasting glucose concentrations, and increased muscle glycogen levels, but there were no changes in glucose tolerance curve and plasma insulin concentrations. These results suggest that regular running program for 4 weeks improve responsiveness of insulin on soleus muscle, but fails to cause improvement of impaired intravenous glucose tolerance in mild degree streptozotocin induced diabetic rats.

Effects of insulin and exercise on glucose uptake of skeletal muscle in diabetic rats.: Jin Hyun Park, Young Woon Kim, Jong Yeon Kim, Suck Kang Lee; Yeungnam Univ J Med. 1990;7(1):29-37. Published online June 30, 1990; DOI: https://doi.org/10.12701/yujm.1990.7.1.29

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Abstract PDF: 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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