Basal and Postprotein Insulin and Glucagon Levels During a High and Low Carbohydrate Intake and Their Relationships to Plasma Triglycerides

The effects of acute and chronic differences in the carbohydrate content of the diet on plasma insulin, glucagon, insulin-glucagon molar ratio (I/G), and triglycerides were studied. Acute effects were studied by varying the carbohydrate content of a single test meal, while chronic effects were determined by varying the carbohydrate content of the diet for a week. A test meal containing 0.6 gm. of gelatin per kilogram plus 0.6 gm. per kilogram of glucose resulted in much higher levels of insulin and I/G (p<0.005), lower glucagon levels (p<0.05), and slightly higher triglycerides (N.S.) than did a meal of 1.2 gm. per kilogram of gelatin alone. One week of a 12-gm. carbohydrate, 2870-calorie diet lowered insulin (p<0.001), I/G (p<0.05), and triglycerides (p<0.001) and increased glucagon (N.S.), whereas a 390-gm. carbohydrate, 2784-calorie intake significantly increased insulin, I/G, and triglycerides (p<0.005) and lowered glucagon (p<0.02) within two days; even greater changes in hormones were observed on a 510-gm. carbohydrate intake. Of those patients in whom a high carbohydrate intake induced a triglyceride rise of at least 40 mg. per deciliter, a significant correlation between the change in I/G and the change in triglycerides was noted (r=0.82; p<0.01). The results are compatible with but do not prove the proposal that pancreatic α and β cells play a mediating role in carbohydrate induction of hyperlipidemia.