Effects of glucose and insulin on fetal glucose oxidation and oxygen consumption.
Glucose and insulin clamp experiments were performed in late-gestation fetal lambs to quantify the separate and combined effects of physiological concentrations of fetal glucose (G; 7.3-62.6 mg/dl) and insulin (I; 2-119 uU/ml) on fetal glucose metabolism and O2 consumption. Fetal glucose utilization rate (GUR) varied from 2.82 to 15.12 mg.min-1.kg-1. Fetal CO2 production from fetal glucose carbon oxidation (CO2Pr) varied from 32 to 234 mumol.min-1.kg-1 and was directly related to G and I [CO2Pr = -0.00868 + 0.00578 (G) + 0.000901 (I) - 0.0000619 (G)2, r = 0.88] and to GUR (CO2Pr = 0.0159 GUR - 0.0130, r = 0.89). CO2Pr accounted for 54.7% of the mean GUR and for 35.9% of the mean umbilical O2 uptake (UO2U), ranging from 26.0% in the control studies to 36.5% in hyperinsulinemic-euglycemic studies and to 45.1% in hyperinsulinemic-hyperglycemic studies. UO2U varied from 0.200 to I [UO2U = 0.303 + [0.000813 (G)] + [0.0000461 (I)], r = 0.89] and to GUR (UO2U = 0.0098 GUR + 0.275, r = 0.91). These results define independent (additive) effects of G and I on glucose oxidation in the late gestation fetal lamb and demonstrate the necessity for considering the levels of both G and I when studying these aspects of fetal metabolism.
Hay
W W
WW
Department of Pediatrics, University of Colorado School of Medicine, Denver 80262.
DiGiacomo
J E
JE
Meznarich
H K
HK
Hirst
K
K
Zerbe
G
G
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002250:Carbon Radioisotopes; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D015309:Glucose Clamp Technique; D006019:Glycolysis / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D010101:Oxygen Consumption / Q000187:drug effects; D011247:Pregnancy; D011865:Radioisotope Dilution Technique; D012756:Sheep
D001786:Blood Glucose; D002250:Carbon Radioisotopes; D007328:Insulin; D005947:Glucose