Ethnicity affects the postprandial regulation of glycogenolysis

1 Division of Endocrinology and 4 Section on Atherosclerosis, Department of Medicine, 2 Department of Pediatrics, Children's Nutrition Research Center, and 3 Department of Community Medicine, Baylor College of Medicine, Houston, Texas We investigated the effect of nutrient intake on glucose metabolism in normal Mexican-Americans ( n = 6) and European-Americans ( n = 6). Subjects were studied after an 18-h fast and after 5-6 h of ingestion of hourly meals that supplied 6.35 or 12.75 µmol glucose · kg 1 · min 1 . Endogenous glucose production (EGP), gluconeogenesis (GNG), and glycogenolysis (GLY) were estimated by mass isotopomer analysis with [U- 13 C]glucose infusions. Fasting EGP, GNG, and GLY did not differ between the groups. Food ingestion lowered the molar rate of GNG by only 31%. However, while consuming the lower quantity of nutrients, Mexican-Americans had higher plasma glucose ( P