TY - JOUR
T1 - Determination of a glucose-dependent futile recycling rate constant from an intraperitoneal glucose tolerance test
AU - Xu, Jun
AU - Lee, W. N.Paul
AU - Xiao, Gary
AU - Trujillo, Chuck
AU - Chang, Vicky
AU - Blanco, Lilia
AU - Hernandez, Felicia
AU - Chung, Beau
AU - Makabi, Sahar
AU - Ahmed, Sayed
AU - Bassilian, Sara
AU - Saad, Mohammed
AU - Kurland, Irwin J.
N1 - Funding Information:
This work was supported by grants from the American Diabetes Association (I.J.K.), and the NIH (DK56090-A1, W.N.P.L.). The GC/MS Facility is supported by PHS Grants P01-CA42710 to the UCLA Clinical Nutrition Research Unit, Stable Isotope Core, and M01-RR00425 to the General Clinical Research Center.
PY - 2003/4/15
Y1 - 2003/4/15
N2 - Increased glucose cycling between glucose and glucose-6-phosphate is characteristic of insulin resistance and hyperglycemia seen with Type II diabetes. Traditionally, glucose cycling is determined by the difference between hepatic glucose output measured with separate [2-3H]glucose and [6-3H]glucose infusions. We demonstrate a novel method for determining hepatic glucose recycling from an intraperitoneal glucose tolerance test (IPGTT). A single tracer, [1, 2-13C2]glucose (a M2 glucose isotopomer), was administered at 1mg/g body weight to 4-month-old C57BL/6 mice. Hepatic glucose recycling was monitored by the appearance of a plasma M1 isotopomer of glucose, which is produced by the action of the pentose cycle on the M2 glucose isotopomer in the liver. The initial M2 enrichment was 56% and decreased to 13% at the end of 3h, and the M1 enrichment peaked at 2h. The ratio of plasma M1/M2 glucose increased linearly with time to ∼25%, and the regression of the M1/M2 ratio against time gives a slope, termed the in vivo glucose-dependent futile recycling rate constant kHR·kHR estimates glucose/glucose-6-phosphate futile cycling, along with glucose recycling through the pentose cycle. These observations demonstrate complex substrate cycling during an IPGTT using a single stable isotope tracer.
AB - Increased glucose cycling between glucose and glucose-6-phosphate is characteristic of insulin resistance and hyperglycemia seen with Type II diabetes. Traditionally, glucose cycling is determined by the difference between hepatic glucose output measured with separate [2-3H]glucose and [6-3H]glucose infusions. We demonstrate a novel method for determining hepatic glucose recycling from an intraperitoneal glucose tolerance test (IPGTT). A single tracer, [1, 2-13C2]glucose (a M2 glucose isotopomer), was administered at 1mg/g body weight to 4-month-old C57BL/6 mice. Hepatic glucose recycling was monitored by the appearance of a plasma M1 isotopomer of glucose, which is produced by the action of the pentose cycle on the M2 glucose isotopomer in the liver. The initial M2 enrichment was 56% and decreased to 13% at the end of 3h, and the M1 enrichment peaked at 2h. The ratio of plasma M1/M2 glucose increased linearly with time to ∼25%, and the regression of the M1/M2 ratio against time gives a slope, termed the in vivo glucose-dependent futile recycling rate constant kHR·kHR estimates glucose/glucose-6-phosphate futile cycling, along with glucose recycling through the pentose cycle. These observations demonstrate complex substrate cycling during an IPGTT using a single stable isotope tracer.
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U2 - 10.1016/S0003-2697(02)00709-1
DO - 10.1016/S0003-2697(02)00709-1
M3 - Article
C2 - 12689833
AN - SCOPUS:0037446351
SN - 0003-2697
VL - 315
SP - 238
EP - 246
JO - Analytical Biochemistry
JF - Analytical Biochemistry
IS - 2
ER -