Mobilization of subcutaneously injected tritiated insulin in rats: Effects of muscular exercise

Berger, Michael; Halban, Philippe A.; Müller, W.; Offord, Robin E.; Renold, A. E.; Vranić, Mladen

doi:10.1007/bf00422259

Cited by 48 publications

(25 citation statements)

References 24 publications

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“…To overcome these problems we have used, as in previous studies (15,(33)(34)(35), semisynthetic [3H]insulin (10,11). This tracer is labeled uniquely on the amino terminal phenylalanine of the insulin B chain.…”

Section: Discussionmentioning

confidence: 99%

Increased Clearance and Degradation of [3H]Insulin in Streptozotocin Diabetic Rats

Philippe¹,

Halban²,

Gjinovci³

et al. 1981

J. Clin. Invest.

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A B S T R A C T The role of the insulin-receptor compartment in the pharmacokinetics of intravenously injected insulin in rats was studied. Since when the animals were again hyperglycemic and hypoinsulinemic. This suggests that down-regulation of insulin receptors had occurred during insulin therapy. These results confirm that a specific compartment for insulin exists (the insulin-receptor compartment) and that this compartment plays an important role in insulin clearance.

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Section: Discussionmentioning

confidence: 99%

Increased Clearance and Degradation of [3H]Insulin in Streptozotocin Diabetic Rats

Philippe¹,

Halban²,

Gjinovci³

et al. 1981

J. Clin. Invest.

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“…The low insulin concentration during exercise also promotes lipolysis, making FFAs available for oxidation by exercising muscle and glycerol available to the liver for gluconeogenesis. In the insulin-treated diabetic patients, plasma insulin concentrations do not decrease during exercise and may even increase substantially if exercise is undertaken within an hour or so of an insulin injection (6,(61)(62)(63). This effect is due to increased absorption of insulin from the subcutaneous tissue, particularly if the injection site is in an exercising part of the body (64).…”

Section: Metabolic Fuel Homeostasis During Exercise In Type I Diabetesmentioning

confidence: 99%

Role and Management of Exercise in Diabetes Mellitus

Horton

1988

Diabetes Care

111

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As more is understood about the physiology of exercise, in both normal and diabetic subjects, its role in the treatment of diabetes is becoming better defined. Whereas people with diabetes may derive many benefits from regular physical exercise, there are also several hazards that make exercise difficult to manage. In type I (insulin-dependent) diabetes, there are risks of hypoglycemia during or after exercise or of worsening metabolic control if insulin deficiency is present. Type II (non-insulin-dependent) diabetic patients treated with sulfonylureas are also at some increased risk of developing hypoglycemia during or after exercise, although this poses less of a problem than with insulin treatment. In individuals treated by diet alone, regulation of blood glucose during exercise is usually not a significant problem and exercise can be used as an adjunct to diet to achieve weight loss and improved insulin sensitivity. When obese type II diabetic patients are treated with very low calorie diets, adequate amounts of carbohydrate must be provided to ensure maintenance of normal muscle glycogen content, particularly if individuals wish to participate in highintensity exercise that places a heavy workload on specific muscle groups. On the other hand, moderateintensity exercise such as vigorous walking can be tolerated by individuals on very low calorie, carbohydrate-restricted diets after an appropriate period of adaptation. A number of strategies can be employed to avoid hypoglycemia in type I diabetic patients, and both type I and II diabetic patients should be examined carefully for long-term complications of their disease, which may be made worse by exercise. These considerations have led many diabetologists to consider exercise beneficial in the management of diabetes for

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“…Previous studies in rats (15), dogs (16), and man (17)(18)(19) have demonstrated that exercise enhances the absorption of insulin from subcutaneous injection sites. The resultant increase in circulating plasma insulin levels could then exert a blood-glucose lowering effect either by inhibiting hepatic glucose production or by stimulating peripheral glucose uptake, or both.…”

Section: Introductionmentioning

confidence: 99%

Synergistic interaction between exercise and insulin on peripheral glucose uptake.

DeFronzo¹,

Ferrannini²,

Sato³

et al. 1981

J. Clin. Invest.

376

237

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A B S T R A C T The interaction of exercise and insulin on glucose metabolism was examined in 10 healthy volunteers. Four study protocols were used: study 1: plasma insulin was raised by -100 ,uU/ml while plasma glucose was maintained at basal levels for 2 h (insulin clamp). Study 2: subjects performed 30 min of bicycle exercise at 40% of VO2 max. Study 3: an insulin clamp was performed as per study 1. Following 60 min of sustained hyperinsulinemia, however, subjects exercised for 30 min as per study 2. Study 4: subjects were studied as per study 3 except that catheters were inserted into the femoral artery and vein to quantitate leg glucose uptake.During the 60-90-min period of hyperinsulinemia (study 1), glucose uptake averaged 8.73±0.10 mg/kg per min. With exercise alone (study 2), the increment in peripheral glucose uptake was 1.43±0.30 mg/kg per min. When hyperinsulinemia and exercise were combined (study 3), glucose uptake averaged 15.06±0.98 mg/kg per min (P < 0.01) and this was significantly (P < 0.001) greater than the sum of glucose uptake when exercise and the insulin clamp were performed separately. The magnitude of rise in glucose uptake correlated closely with the increase in leg blood flow (r = 0.935, P < 0.001), suggesting that the synergism is the result of increased blood flow and increased capillary surface area to exercising muscle. More than 85% of total body glucose metabolism during studies 1 and 3 was accounted for by skeletal muscle uptake.These results demonstrate that (a) insulin and exercise act synergistically to enhance glucose disposal in man, and (b) muscle is the primary tissue responsible for the increase in glucose metabolism following hyperinsulinemia and exercise.

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Mobilization of subcutaneously injected tritiated insulin in rats: Effects of muscular exercise

Cited by 48 publications

References 24 publications

Increased Clearance and Degradation of [3H]Insulin in Streptozotocin Diabetic Rats

Increased Clearance and Degradation of [3H]Insulin in Streptozotocin Diabetic Rats

Role and Management of Exercise in Diabetes Mellitus

Synergistic interaction between exercise and insulin on peripheral glucose uptake.

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