Effects of hyperglycemia on glucose production and utilization in humans. Measurement with (3H)-2-, (3H)-3-, and (14C)-6-glucose
Studies with tritiated isotopes of glucose have demonstrated that hyperglycemia per se stimulates glucose utilization and suppresses glucose production in humans. These conclusions rely on the assumption that tritiated glucose provides an accurate measure of glucose turnover. However, if in the presence of hyperglycemia the isotope either loses its label during futile cycling or retains its label during cycling through glycogen, then this assumption is not valid. To examine this question, glucose utilization and glucose production rates were measured in nine normal subjects with a simultaneous infusion of (/sup 3/H)-2-glucose, an isotope that may undergo futile cycling but does not cycle through glycogen; (/sup 14/C)-6-glucose, an isotope that may cycle through glycogen but does not futile cycle; and (/sup 3/H)-3-glucose, an isotope that can both undergo futile cycling and cycle through glycogen. In the postabsorptive state at plasma glucose concentration of 95 mg X dl-1, glucose turnover determined with (/sup 14/C)-6-glucose (2.3 +/- 0.1 mg X kg-1 X min-1) was greater than that determined with (3/sup 3/H)glucose (2.1 +/- 0.1 mg X kg-1 X min-1, P = 0.002) and slightly less than that determined with (/sup 3/H)-2-glucose (2.7 +/- 0.2 mg X kg-1 X min-1, P = 0.08). Plasma glucose was then raised from 95 to 135 to 175 mg X dl-1 while insulin secretion was inhibited, and circulating insulin, glucagon, and growth hormone concentrations were maintained constant by infusion of these hormones and somatostatin. Glucose production and utilization rates determined with (/sup 14/C)-6-glucose continued to be less than those determined with (/sup 3/H)-2-glucose and greater than those seen with (/sup 3/H)-3-glucose.
- Research Organization:
- Mayo Clinic, Rochester, MN
- OSTI ID:
- 5272951
- Journal Information:
- Diabetes; (United States), Journal Name: Diabetes; (United States) Vol. 6; ISSN DIAEA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
BIOSYNTHESIS
CARBOHYDRATES
CARBON 14 COMPOUNDS
ETIOLOGY
GLUCAGON
GLUCOSE
HEXOSES
HORMONES
HYPERGLYCEMIA
INSULIN
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
METABOLISM
MONOSACCHARIDES
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PEPTIDES
POLYPEPTIDES
PROTEINS
SACCHARIDES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS