title: Extracellular glucose can fuel metabolism in red blood cells from high glycemic Atlantic cod (Gadus morhua) but not low glycemic short-horned sculpin (Myoxocephalus scorpius).
abstract: Energy metabolism was assessed in red blood cells (RBCs) from Atlantic cod and short-horned sculpin, two species that have markedly different levels of blood glucose. The objective was to determine whether the level of extracellular glucose has an impact on rates of glucose metabolism. The blood glucose level was 2.5 mmol l(-1) in Atlantic cod and 0.2 mmol l(-1) in short-horned sculpin, respectively. Oxygen consumption, lactate production and glucose utilization were measured in whole blood and related to grams of RBCs. Glucose utilization was assessed by measuring both glucose disappearance and the production of (3)H2O from [2-(3)H]-glucose. RBCs from both species have an aerobic-based metabolism. In Atlantic cod, extracellular glucose is sufficient to provide the sum of glucosyl equivalents to support both oxidative metabolism and lactate production. In contrast, extracellular glucose can account for only 10% of the metabolic rate in short-horned sculpin RBCs. In both species, about 70% of glucose enters the RBCs via facilitated transport. The difference in rates of extracellular glucose utilization is related to the extremely low levels of blood glucose in short-horned sculpin. In this species energy metabolism by RBCs must be supported by alternative fuels.
authors.affiliation: Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL A1C 5S7, Canada wdriedzic@mun.ca.
authors.forename: William R
authors.initials: WR
authors.lastname: Driedzic
authors.affiliation: Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL A1C 5S7, Canada.
authors.forename: Kathy A
authors.initials: KA
authors.lastname: Clow
authors.affiliation: Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL A1C 5S7, Canada.
authors.forename: Connie E
authors.initials: CE
authors.lastname: Short
mesh_terms: D000818:Animals; D004734:Energy Metabolism / Q000502:physiology*; D004912:Erythrocytes / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D048389:Gadus morhua / Q000378:metabolism / Q000502:physiology*; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010473:Perciformes / Q000378:metabolism / Q000502:physiology*; D013045:Species Specificity
chemical_list: D019344:Lactic Acid; D006003:Glycogen; D005947:Glucose
keywords: Cytochalasin B; Glucose metabolism; Red blood cell; [2-3H]-glucose