Lactate Movements in the Term Human Placenta in situ

Abstract

Movements of lactate through the human placenta in situ were derived from maternal and fetal blood sampling performed under conditions that approximate as closely as possible the normal fetal metabolic state. It is reported that, at the end of pregnancy, the human fetus produces lactate which is transferred to the placenta. The actuality of this lactate transfer coupled with proton transfer is discussed taking into account the results of multiple linear regression analysis determined between the umbilical arterio-venous lactate differences and fetal and maternal lactate and proton concentrations. It is finally assumed that this lactate is partly metabolized in the placenta, the remaining part being transferred from the placenta to the mother.

Cellular Expression of the Monocarboxylate Transporter (MCT) Family in the Placenta of Mice

“…In humans and other mammals, the concentration of lactate in the fetal circulation is known to be higher than in the maternal circulation [2][3][4][5][6]. Some researchers consider the major source of lactate in the fetal circulation of humans to be the fetus itself due to the active anaerobic metabolism of fetus-that must be discharged into the maternal circulation [3][4][5].…”

“…Some researchers consider the major source of lactate in the fetal circulation of humans to be the fetus itself due to the active anaerobic metabolism of fetus-that must be discharged into the maternal circulation [3][4][5]. On the other hand, fetal tissues of sheep effectively utilize lactate as a metabolic energy source, supplied by placental lactate production or transfer from maternal blood [2,6].…”

“…On the other hand, fetal tissues of sheep effectively utilize lactate as a metabolic energy source, supplied by placental lactate production or transfer from maternal blood [2,6]. The most likely mechanism of lactate transfer through the placenta involves a specific carrier-mediated system, being coupled with proton transfer [4,7,8].…”

“…Among the glucose transporter isoforms, GLUT1 and GLUT3 are 4 localized in the cell membrane of syncytiotrophoblasts in mammals [9,10]. Another set of placental perfusion studies and isolated plasma membrane studies have demonstrated that lactate is transferred across the placental barrier by means of streospecific (between L-and D-lactate) transporters [11][12][13], and the movement is mediated by a carrier-dependent transporter resembling the lactate/H + co-transporters with a broad distribution throughout the body.…”

The Role of Mitochondria in Syncytiotrophoblast Cells: Bioenergetics and Steroidogenesis

“…The incubation of trophoblastic cells, perfused explants or placentas, produces lactic acid as a result of anaerobic glycolysis used by the fetus (Battaglia, 1989;Piquard et al, 1990). The radioactivity of glucose labeled with 14 C showed the following distribution: lactate 60-69%, glycogen 1.3-4.8%, pentose pathway 5%, fatty acids 0.7-1.4% and CO 2 1.6-2.4% (Desoye & Shafrir, 1994).…”