Abstract

The influence of exercise on leg and splanchnic exchange of substrates was examined in eight insulin-dependent diabetics 24 h after withdrawal of insulin and in eight healthy controls studied at rest and after 40 min of bicyle ergometer exercise at 55-60 of maximal capacity. In four of the diabetic subjects, basal arterial ketone acid levels were 3-4 mmol/l (ketotic diabetics) and in the remainder, below 1 mmol/l (nonketotic diabetics). Free fatty acid (FFA) turnover and regional exchange were evaluated with 14 C-labeled oleic acid. Leg uptake of blood glucose rose 13-18-fold during exercise in both the diabetics and controls and accounted for a similar proportion of the total oxygen uptake by leg muscles (25-28) in the two groups. In contrast, leg uptake of FFA corresponded to 39 of leg oxygen consumption in the diabetic group but only 27 in controls. Systemic turnover of oleic acid was similar in the two groups. It is concluded that a) glucose uptake by exercising muscle in hyperglycemic diabetics is not different from that of controls; b) splanchnic glucose output rises during exercise to a similar extent in diabetics and controls,while uptake of gluconeogenic substrates is markedly higher in diabetics and accounts for a greater proportion of total splanchnic glucose output; c) exercise in diabetic patients with mild ketosis is associated with a rise in blood glucose and FFA levels as well as augmented splanchnic production and peripheral uptake of ketone bodies. Verf.-Referat