M.J. Whichelow

EFFECT OF DIET, SULPHONYLUREAS, AND PHENFORMIN ON PERIPHERAL GLUCOSE UPTAKE IN DIABETES AND OBESITY

Abstract Peripheral glucose metabolism has been studied during oral glucose-tolerance tests in obese non-diabetics, before and after weight reduction by diet or oral phenformin therapy, and in maturity-onset diabetics before and after phenformin therapy, sulphonylurea therapy, or combined phenformin and sulphonylurea therapy. The results confirm earlier work that peripheral glucose uptake is reduced in obesity and diabetes. In non-diabetic subjects, weight reduction but not phenformin therapy caused a striking increase in glucose uptake. In the diabetics, successful therapy with any of the drugs, as gauged by a substantial fall in the fasting blood-sugar, was associated with a significant increase in glucose uptake. These findings suggest that the block to peripheral glucose uptake in obesity is different from that in diabetes, and that both blocks are reversible.

The effect of mild exercise on glucose uptake in human forearam tissues in the fasting state and after oral glucose administration

Peripheral glucose uptake was found to be comparable in the right and left arms at rest in fasting non-diabetic and diabetic subjects. In the fasting state, glucose uptake and blood flow in the exercising arm was higher than in the resting arm. Following the oral administration of 50 Gm. glucose, glucose uptake rose both in the resting limb and, to an even greater extent, in the exercising limb in the non-diabetic subjects. In the diabetics, the findings were variable, and no effect of exercise could be detected in 2 insulin-dependent diabetics deprived of insulin The mechanism of action of the exercise effect and its dependence on circulating insulin is discussed.

Effect of exercise on peripheral uptake of 131I-iodo insulin and glucose in nondiabetics☆

The effect of exercise on insulin and glucose uptake in peripheral tissues in nondiabetic subjects has been studied by comparing the results of intraarterial injections of 131I-iodo insulin into resting arms with those of a similar injection when the forearm muscles were exercising. In the resting state, statistically significant linear correlations between the insulin concentration achieved and the insulin uptake from the blood and between the insulin uptake and the subsequent increase in glucose uptake were confirmed. Exercise markedly increased insulin uptake in relation to insulin concentration but did not affect the relationship between glucose uptake and insulin uptake. The simplest explanation for the effect of exercise increasing glucose uptake by muscle is an increased insulin uptake through the larger capillary bed opened up in response to muscle contraction.