157 Release of Placental Growth Hormone (hGH-V) in The Dual in vitro Placenta Perfusion Model

Background: hGH-V is a variant of pituitary hGH-N. High maternal hGH-V concentrations are correlated with fetal growth (1). It is not clear, if hGH-V stimulates directly fetal growth as a growth factor, or indirect via modulation of the maternal metabolism. There is a new highly specific assay available to measure hGH-V. The aim of our study was to measure placental release rates of hGH-V into the maternal and fetal circulation.Methods: Placentas (n=6) were obtained after uncomplicated pregnancies and written informed consent of the mothers at term. Dual in vitro placenta perfusion was performed for 4,5h. Control parameters for placental function were permeabilities of creatinine and antipyrine, as well as glucose consumption and lactate production of the perfused cotyledons. The release rates of Leptin (RIA), hCG (ELISA) and hGH-V (1) into the maternal and fetal circulation were measured.Results: Placental hGH-V was only released into the maternal circulation of the dual in vitro placenta perfusion model with a release rate of 2,8±2,4 ng/g/min (mean±SD). The release rate for leptin was 239±90 ng/g/min (maternal 98%, fetal 2%) and for hCG 64±37 IU/g/min (99,4% maternal, 0,6% fetal).Conclusion: We could show first the directional release of placental hGH-V only into the maternal circulation in the dual in vitro perfused placenta. The significant influence of hGH-V on fetal growth is a result of the modulation of the maternal metabolism rather than a direct stimulatory effect on fetal growth. 1Z.Wu et al. J Clin Endocrinol Metab 2003, 88(2): 804– 811