Fuel oxidation by insulin-dependent diabetics during late pregnancy in response to an oral glucose load.

1. To determine the oxidative response to a 50-g oral glucose challenge by diabetic women during late pregnancy under a more intensive therapeutic regimen than is conventionally employed, six normal pregnant women and ten insulin-dependent pregnant diabetic women were studied during the third trimester. Fuel (carbohydrate and lipid) oxidation rates were determined by indirect calorimetry, blood levels of substrates and C-peptide were measured directly, and glucose metabolism data (oxidation and nonoxidative metabolism) were estimated for both groups at the postabsorptive state and for the 2-h period following glucose ingestion.

Carbohydrate, lipid and amino acid metabolism of insulin-dependent diabetic patients regulated by an artificial beta-cell unit.

To characterize the effects of artificial beta-cell directed insulin therapy on carbohydrate, lipid and amino acid metabolism, five insulin-dependent diabetic patients were challenged with a 100-g glucose meal while on conventional (single or split mixed insulin injections) therapy and again after 72 hr on an artificial beta-cell unit. It was verified that the high levels of blood glucose of the conventionally treated diabetics were marked reduced toward normal by the artificial beta-cell therapy, while the blood lactate and pyruvate concentrations increased significantly to levels higher than in normal controls. The elevated levels of FFA, glycerol, and ketones in the diabetics under conventional therapy were entirely normalized during the artificial beta-cell regulation.

Artificial beta-cell promotes positive nitrogen balance and whole body protein synthesis in insulin-dependent diabetic subjects.

To assess the effects of artificial beta-cell-directed insulin therapy on protein metabolism in patients with diabetes mellitus, nitrogen balance, urea production, and whole body protein turnover were determined in five type I insulin-dependent subjects and five age- and sex-matched controls. Each diabetic participant was studied over two 4-day periods while receiving conventional insulin therapy (one or two daily injections of short and intermediate acting insulin) or insulin delivered by the artificial beta-cell. While the diabetic participants received conventional insulin therapy, nitrogen balance, urea production, whole body protein turnover, and protein synthesis and breakdown rates did not differ significantly from the control group.

Dietary carbohydrate, a Big Mac, and insulin requirements in type I diabetes.

Using the artificial beta-cell (Biostator), we determined the insulin requirements in five nonobese type I (insulin-dependent) diabetic subjects who received isocaloric 40 and 60% mixed-carbohydrate diets in a crossover randomized fashion for 4 days, each day consisting of four equal meals. This was followed on day 5 by a "Big Mac Attack" lunch consisting of a Big Mac, french fries, and milk shake. Insulin requirements to maintain normoglycemia were calculated for each 24-h period and for the 2 h after each meal.

Role of muscle in CO2 production after oral glucose administration in man.

A significant increase in CO2 production, reflecting carbohydrate oxidation and/or fat synthesis, is observed in normal subjects after the ingestion of glucose. The anatomic site(s) of this CO2 production has not yet been localized, although liver and muscle are logical considerations. To assess the contribution of skeletal muscle to this process, we measured whole-body and forearm CO2 flux in normal, postabsorptive subjects after the ingestion of 100 g of glucose and calculated their total muscle CO2 production.