AJP - Endocrinology and Metabolism, Vol 239, Issue 1 39-E44, Copyright © 1980 by American Physiological Society
Transfer of carbon atoms among circulating glucose, alanine, and lactate in pancreatectomized dogs
G. Hetenyi Jr, R. A. Layberry, D. M. Foster and M. Berman
The rates of transfer of carbon atoms (mg C . kg body wt-1 . min-1) among
plasma glucose, alanine, and lactate have been calculated in
pancreatectomized dogs from the tracer concentration versus time curves in
the plasma after an intravenous injection of either [2,3-3H]- and
[U-14C]alanine or [3-3H]- and [U-14C]glucose. The calculations were based
on an integrated kinetic model derived earlier from experimental data. In
comparison to normal dogs, in insulin-deprived pancreatectomized dogs, the
rate of turnover of glucose (mg C . kg-1 . min-1) is increased about
twofold, but the turnover rates of lactate and alanine are not changed
significantly. About twice as much carbon is transferred from lactate to
glucose, whereas the transfer of carbon from alanine is increased by 47%.
Carbon transfer to glucose from unidentified sources is also doubled. In
conclusion, in the pancreatectomized dog, gluconeogenesis is increased not
by an increased production of alanine and lactate but by an increased
diversion of their carbon atoms to glucose at the expense of other
pathways.
