Fetal-Maternal Transfer of [H³]-6β-Hydroxycortisol in the Pregnant Ewe

Summary

Distribution and fetomaternal transfer of 6β-hydroxy-cortisol (6β-OHF) was studied using serial sampling following injection of tritium labelled 6β-OHF into various fluid compartments in the chronically cannulated unaesthesized pregnant ewe. There was a rapid transfer of 6β-OHF from the fetal circulation into amniotic fluid and maternal blood. In contrast, the maternal → fetal transfer of this steroid metabolite was considerably less. The sequence of appearance of 6β-OHF in fetal blood and amniotic fluid following injection into maternal blood suggests that this steroid is first transferred across the placenta to fetal blood before gaining entry into the amniotic fluid space. The half-lives of 6β-OHF after initial equilibration in maternal plasma, fetal plasma and amniotic fluid were 2.0 h, 5.1 h and 8.9 h respectively. The amniotic sac appears to contain a relatively static pool of 6β-OHF and may act as a “trap” for 6β-OHF in the ovine conceptus.

Key-Words

6β-Hydroxycortisol - Pregnancy - Fetal-Maternal Transfer