AJP - Endocrinology and Metabolism, Vol 239, Issue 3 208-E214, Copyright © 1980 by American Physiological Society
Glucose and lactate metabolism in vivo in ovine fetus
R. L. Prior
The metabolism of glucose and lactate by the ovine fetus (123-128 days of
gestation) was studied; a primed, continuous infusion of [2-3H]glucose and
[U-14C]lactate into the brachial vein of six fetuses was used. Fetal plasma
lactate concentrations averaged 2.12 +/- 0.25 mM and glucose concentrations
averaged 9.3 +/- 1.3 mg/100 ml. Total plasma turnover of lactate was 5.22
+/- 0.7 nmol/h and that of glucose was 3.48 +/- 0.63 nmol x h-1 x kg fetal
weight-1. Lactate was converted to glucose at a rate of 1.35 +/- 0.64 mmol
x h-1 x kg fetal weight-1, which represented 21.6 +/- 6.0% of the lactate
turnover. The percentage of glucose coming from lactate was 48.9 +/- 15.2.
The specific activity of maternal plasma glucose was less than 4% of the
specific activity of glucose observed in fetal plasma. No radioactivity
could be detected in maternal plasma lactate. The data show that the ovine
fetus or the fetal-placental unit can convert lactate to glucose by days
123-128 of gestation. A general model presented describes carbohydrate
metabolism in the ovine placenta and fetus.
