Lower arterial glucose concentrations in lambs with aortopulmonary shunts after an 18-hour fast.
Spontaneously occurring hypoglycemia has been described in children with severe acute congestive heart failure. Hypoglycemia may be the result of an increase in glucose utilization in tissues, a decrease in glucose production, or a decrease in the dietary intake of nutrients. To determine whether hypoglycemia may also occur in congenital heart disease with volume overloading, we investigated glucose metabolism during and after an 18-hour fast in nine lambs with an aortopulmonary left-to-right shunt and nine control lambs. Plasma levels of hormones involved in the endocrine control of glucose metabolism were determined. The glucose production rate (rate of appearance [Ra]) was studied using [U-13C]glucose. Gluconeogenesis through the Cori cycle was estimated by measuring glucose 13C recycling. The arterial glucose concentration (3,409 +/- 104 v 4,338 +/- 172 micromol/L, P < .001) and Ra of glucose (16.97 +/- 0.89 v 25.49 +/- 4.28 micromol x min(-1) x kg(-1), P < .05) were lower in shunt versus control lambs. There were no differences in hormone levels between control and shunt lambs. Fractional glucose 13C recycling via the Cori cycle (6.9% +/- 2.8% v 7.1% +/- 2.5%) and gluconeogenesis from pyruvate and lactate (1.24 +/- 0.58 v 1.95 +/- 0.67 micromol x min(-1) x kg(-1)) were similar in both groups of lambs. The sum of glycogenolysis and gluconeogenesis from precursors other than pyruvate and lactate was lower in shunt versus control lambs (15.73 +/- 1.07 v 23.54 +/- 4.27 micromol x min(-1) x kg(-1), P < .05). In conclusion, after an 18-hour fast, the arterial glucose concentration is lower in lambs with aortopulmonary shunts. This lower glucose concentration is associated with a decreased glucose production rate. In shunt lambs, glycogenolysis is decreased, while there is no difference in gluconeogenesis or hormonal control.
Beaufort-Krol
G C
GC
Beatrix Children's Hospital, Division of Pediatric Cardiology, University of Groningen, The Netherlands.
Takens
J
J
Smid
G B
GB
Molenkamp
M C
MC
Zijlstra
W G
WG
Kuipers
J R
JR
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002247:Carbon Isotopes; D004195:Disease Models, Animal; D005215:Fasting; D005943:Gluconeogenesis; D006019:Glycolysis; D018611:Heart Bypass, Left; D006333:Heart Failure / Q000378:metabolism*; D006439:Hemodynamics; D007003:Hypoglycemia / Q000378:metabolism*; D012756:Sheep
D001786:Blood Glucose; D002247:Carbon Isotopes