Galactose clearance and carbohydrate metabolism across the gastrointestinal tract in the newborn lamb.
We prepared 16 newborn lambs with chronically indwelling catheters in the portal vein, mesenteric vein, femoral vein, and femoral artery to study galactose clearance, portal venous blood flow, and carbohydrate metabolism across the gastrointestinal (GI) tract. Galactose clearance was measured by infusing galactose into the femoral vein to achieve a steady-state galactose concentration in the femoral artery. We observed a curvilinear relationship between galactose clearance and the steady-state galactose concentration. The relationship could be modeled as an apparent Michaelis-Menten system: Clearance = Vmax/(Km + [Gal]ssa), where Vmax = 17.0 +/- 2.5 mg/min/kg body weight and Km = 11.0 +/- 0.4 mg/dL. Substrate/oxygen quotients across the viscera drained by the portal vein were measured in the fasted state and during systemic galactose infusion. A net uptake of glucose and galactose by the GI tract was found with quotients of 0.19 +/- 0.07 and 0.05 +/- 0.02, respectively. There was a relatively large net efflux of lactate across the portal circulation, with a quotient of -0.13 +/- 0.03. The indicator-dilution technique was used to estimate portal venous blood flow (PVBF) in the neonatal period with a resting, fasted state value of 92.8 +/- 4.4 mL/min/kg body weight.(ABSTRACT TRUNCATED AT 250 WORDS)
Kaempf
J W
JW
Department of Pediatrics, University of Colorado School of Medicine, Denver.
Battaglia
F C
FC
Sparks
J W
JW
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001783:Blood Flow Velocity; D050260:Carbohydrate Metabolism; D004064:Digestive System / Q000378:metabolism*; D005263:Femoral Artery; D005268:Femoral Vein; D005690:Galactose / Q000008:administration & dosage / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D007408:Intestinal Absorption; D007700:Kinetics; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008642:Mesenteric Veins; D008657:Metabolic Clearance Rate; D010101:Oxygen Consumption; D011169:Portal Vein / Q000502:physiology; D012756:Sheep
D007773:Lactates; D019344:Lactic Acid; D005947:Glucose; D005690:Galactose