Abstract
The transfer of14C-labelledd- orl-lactate (test substance) relative to3H-l-glucose (control substance, extracellular marker) into the trophoblast of the isolated guinea pig placenta was determined during an open loop perfusion on both sides. Using a single passage, paired tracer dilution technique, the maximal lactate uptake (U max) was derived from the venous concentration ratio of lactate tol-glucose.
A significant metabolism ofl-lactate was not observed. The lactate uptake, which occurred in all placentas studied, was not significantly different on the fetal and maternal side. Within one placenta thel-lactate uptake was always higher than thed-lactate uptake. The uptake of bothl- andd-lactate could be inhibited by phloretin. The lactate uptake was inversely correlated with the pH of the perfusate fluid within the range from 6.2–8. A first order saturation kinetic (Hofstee-plot) was used to approximate the relationship between thel-lactate uptake and the chemicall-lactate concentration. We conclude that similar lactate carriers exist in the membranes on both the maternal and the fetal side of the trophoblast.
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Leichtweiß, H.P., Schröder, H. l-Lactate andd-lactate carriers on the fetal and the maternal side of the trophoblast in the isolated guinea pig placenta. Pflugers Arch. 390, 80–85 (1981). https://doi.org/10.1007/BF00582716
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DOI: https://doi.org/10.1007/BF00582716