ISOTOPIC ESTIMATION OF THE HEPATIC GLUCOSE BALANCE IN-VIVO

Conventional determination of 'hepatic glucose production' in the refed state is based on the 30-year-old Steele model, which omits glucose ⇆ glucose-6P cycling. Using the more complete model, conventional hepatic glucose production is shown to be a complex ratio of fluxes, and not a simple physiological flux. Our new model allows some prospective isotopic approaches to the estimation of glucose-6-phosphatase and glucokinase fluxes, and thus real net hepatic glucose production or uptake. © 1994 Academic Press Limited.