Constant infusion and bolus injection of stable-label tracer give
reproducible and comparable estimates of fasting hepatic glucose
output.
Hovorka, Roman, David J A Eckland, David Halliday, Sally Lettis,
Claire E Robinson, Peter Bannister, Malcolm A Young, and Alan Bye.
Metabolic Modelling Group, Centre for Measurement and Information
in Medicine, City University, Northampton Square, London, EC1V 0HB,
UK, Glaxo-Wellcome Research and Development plc, Greenford Road,
Greenford, Middlesex, UB6 0HE, UK, MRC Human Metabolism Research
Group, Unit of Metabolic Medicine, St Mary''s Hospital Medical
School, Mint Wing, Norfolk Place, London W2 1PG, UK
APStracts 4:0054E, 1997.
We have investigated the reproducibility of fasting hepatic glucose
output (HGO) estimates using isotope dilution methodology of stable
-label tracers. Six normal subjects were studied on two occasions one
week apart. After an overnight fast, the subjects received a bolus
injection of 7mg/kg of U-13C-glucose and simultaneously, a primed
constant infusion of 0.05mg/kg/min of 6,6-2H-glucose. The bolus
injection provided one estimate of HGO (HGOBOL), the constant
infusion provided two three estimates of HGO, namely HGO at two hours
(HGOINF2), and HGO at four hours (HGOINF4) (both assuming steady
-state conditions)., and HGO at two hours (HGOINF-NSS) (not assuming
steady-state conditions). All estimates were similar in value;
HGOINF-NSS HGOBOL was highest followed by HGOINF2, HGOINF2, and
HGOINF4 (2.34 0.23, 2.30 0.11, 2.17 0.12, 2.01 0.13mg/kg/min; mean
SE). The constant infusion gave highly reproducible results. In the
case of HGOINF2, the within subject CV was only 3% compared to 5% of
HGOINF4 and 6% of HGOINF-NSS. . The reproducibility of HGOBOL was
comparable with the within subject CV of 7%. We conclude that a
constant infusion and a bolus injection of stable-label tracer give
reproducible and comparable estimates of HGO. (Accepted for Modelling
in Physiology section)
Received 3 June 1996; accepted in final form 22 January 1997.
APS Manuscript Number E269-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 12 March 1997