title: Ethnicity affects the postprandial regulation of glycogenolysis.
abstract: 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 micromol 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 < 0.05), a 39% higher rate of EGP (P < 0.05), and a 68% (P < 0.025) higher rate of GLY than the European-Americans. At the higher intake, EGP and GLY were suppressed completely in both groups. There was a linear relationship between insulin concentrations, EGP, and GLY in both groups, but the slope of the line was significantly (P < 0.05) greater in the European-Americans. We conclude that the sensitivity of GLY to nutrient intake differs between ethnic groups and that this may play a role in the increased predisposition of Mexican-Americans to type II diabetes.
authors.affiliation: Division of Endocrinology, Baylor College of Medicine, Houston, Texas, USA. ashokbf@bcm.tmc.edu
authors.forename: A
authors.initials: A
authors.lastname: Balasubramanyam
authors.forename: S
authors.initials: S
authors.lastname: McKay
authors.forename: P
authors.initials: P
authors.lastname: Nadkarni
authors.forename: A S
authors.initials: AS
authors.lastname: Rajan
authors.forename: A
authors.initials: A
authors.lastname: Garza
authors.forename: V
authors.initials: V
authors.lastname: Pavlik
authors.forename: J A
authors.initials: JA
authors.lastname: Herd
authors.forename: F
authors.initials: F
authors.lastname: Jahoor
authors.forename: P J
authors.initials: PJ
authors.lastname: Reeds
mesh_terms: D000328:Adult; D044466:Asian People; D001786:Blood Glucose; D002247:Carbon Isotopes; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology; D004734:Energy Metabolism / Q000502:physiology; D020022:Genetic Predisposition to Disease; D005943:Gluconeogenesis / Q000502:physiology; D005947:Glucose / Q000096:biosynthesis*; D005951:Glucose Tolerance Test; D006003:Glycogen / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000208:ethnology*; D007328:Insulin / Q000097:blood; D007700:Kinetics; D019344:Lactic Acid / Q000097:blood; D008297:Male; D017058:Mexican Americans / Q000235:genetics; D008875:Middle Aged; D019518:Postprandial Period / Q000502:physiology*; D044465:White People
chemical_list: D001786:Blood Glucose; D002247:Carbon Isotopes; D007328:Insulin; D019344:Lactic Acid; D006003:Glycogen; D005947:Glucose