Lactate carriers in the artificially perfused human term placenta.
Thirty-two isolated cotyledons from human term placentae were perfused artificially with a tissue culture medium on the maternal and the fetal side. The transfer and uptake of labelled L-lactate and D-lactate (test substance) relative to L-glucose (reference substance, extracellular marker) were investigated in steady-state experiments (n = 9) and in a single passage paired tracer dilution technique (n = 23). The L-lactate transfer exceeded the L-glucose transfer two to three times. The L-lactate uptake into the trophoblast--both from the maternal and the fetal side--was more than three times that of D-lactate. L-lactate transfer and uptake were inhibited by phloretin. The L-lactate transfer showed a saturation kinetic at increasing chemical concentrations of lactate. It is concluded that lactate carriers exist both in the maternal and fetal side of the trophoblast.
D004058:Diffusion; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007773:Lactates / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010477:Perfusion; D010693:Phloretin / Q000494:pharmacology; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D014327:Trophoblasts / Q000378:metabolism
D007773:Lactates; D005947:Glucose; D010693:Phloretin