Improvement in jejunal enzyme adaptation in obese adult-onset diabetic patients following a 30-day fast.

The adaptive responses of gastrointestinal enzymes, glucose tolerance, and plasma insulin to diet, folic acid, and insulin of five obese adult-onset diabetic patients were studied before and after a 30-day fast. Their data were compared to the adaptive responses of gastrointestinal enzymes to diet, folic acid, and insulin of 15 normal male volunteer subjects, ages 18 to 24. Each group during each testing period received a carbohydrate diet (50% calories as carbohydrate consisting of 1/2 glucose and 1/2 fructose) and a noncarbohydrate diet (70% of calories as corn oil and 30% as sodium caseinate) each without and with folic acid (5 mg three times per day). The effect of insulin was studied only on the carbohydrate diet plus folic acid. Our data demonstrate that obese adult-onset diabetic patients have an impaired adaptive response of jejunal carbohydrate-metabolizing enzyme activities (hexokinase, pyruvate kinase, fructose-1-6-diphosphate aldolase, fructosediphosphatase) to dietary carbohydrate, oral folic acid, and insulin when compared to normal subjects and nondiabetic obese patients. Following a 30-day fast, the obese diabetic patients showed an improvement in glucose tolerance, hyperinsulinemia, and the adaptive response of the jejunal carbohydrate-metabolizing enzyme activities to dietary carbohydrate, folic acid, and insulin. The greatest improvement in the adaptive response of the jejunal enzyme activities occurred on the carbohydrate diet.