Glucose and lactate metabolism in vivo in ovine fetus.
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.
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D005947:Glucose / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism*; D008431:Maternal-Fetal Exchange; D008433:Mathematics; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D012756:Sheep / Q000378:metabolism*
D001786:Blood Glucose; D007773:Lactates; D005947:Glucose