Abstract
With advancing gestation, growth of the placenta stops before the deceleration of fetal growth, and complications related to placental insufficiency become more corrmon. It has been postulated that the fetus “outgrows” its placenta. We have compared the metabolic properties (purine nucleotide synthesis and their catabollsm in response to oxygen and glucose deprivation) of trophoblastic cells, cultured from first (I) and third (III) trimester human placentae and shown by Inmunofluorescence (cytokeratin) and hormone production (chorionic gonadotropin) to retain their specialized trophoblastic character in primary culture.
Purine synthesis de novo (14-C-formate incorporation) In I was two orders of magnitude lower than in fetal fibroblasts, but even lower (1/4) in III. The rate of 14-C-hypoxanthlne phosphoribosylation was at least 10-fold higher than de novo synthesis in both I and III, and unresponsive to high extracellular Pi. ATP level or energy charge (EC) were not influenced by glucose or oxygen deprivation for 8 hr, but 2-deoxyglucose caused a fall in prelabeled ATP to 1/5 and in EC to 0.42-0.46 (control 0.66-0.71) in 30 min in both I and III. Inhibition of oxidative phosphorylation by rotenone had similar effects than 2-deoxyglucose in III, but significantly more delayed in I.
We conclude that human trophoblast at term is metabolically less active and less tolerant to energy substrate deprivation than early in gestation.
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Raivio, K., Vettenranta, K. 123 CHANGES IN TROPHOBLASTIC PURINE METABOLISM WITH AGING OF THE PLACENTA. Pediatr Res 24, 131 (1988). https://doi.org/10.1203/00006450-198807000-00147
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DOI: https://doi.org/10.1203/00006450-198807000-00147