CORRECTION FACTOR FOR THE ESTIMATION OF PLASMA-GLUCOSE SYNTHESIS FROM THE TRANSFER OF C-14 ATOMS FROM LABELED SUBSTRATE INVIVO - PRELIMINARY-REPORT

Based on a previously designed method for the estimation of the contribution of C-atoms by acetylcoenzyme A to the hepatic oxaloacetate pool, the loss of 14C-atoms on their way from a precursor to plasma glucose due to 'metabolic exchange' was estimated in normal and diabetic dogs and in normal rats. Due to this loss of 14C-atoms, the rates of gluconeogenesis when calculated from the transfer of 14C-atoms from precursors (other than glycerol) are underestimated by a factor of 2.2 +/- 0.07 in normal, 1.8 +/- 0.05 in diabetic dogs, and by 1.55 +/- 0.04 in normal rats.