Human embryonal extracts modulate placental function in the first trimester: effects of visceral tissues upon...

We investigated the effect of human first trimester fetal visceral organ extracts upon placental function, as evidenced by secretion of human chorionic gonadotropin and progesterone in explant cultures of 7-10 weeks gestational age trophoblast. Certain alcohol/water or water extracted embryonal tissues, in highly diluted solutions (1:100-1:2,000 final) had significant effects upon secretion of both hormones. The alcohol/water extract produced an opposite effect. This inhibitory effect was also seen when pulses of the water extract were added to the superfused trophoblast. Both heat inactivation at 57 degrees C and treatment with 10 microM p-chloromercurobenzoate eliminated the inhibitory effect, which suggests that the compounds in question are proteinaceous. Also dialysis with exclusion of less than 8,000 daltons abolished the inhibitory effect seen with the untreated water extract. The alcohol/water lung extract at 9 weeks inhibited, while at 10 weeks it stimulated P4 secretion. The water extracted lung had no effect upon P4 secretion. The alcohol/water extract of kidney had no consistent effect upon hCG secretion. The water extract effect was inhibitory. The effect of alcohol/water extract at 9 weeks upon P4 secretion was inhibitory while at 11 weeks it was stimulatory. The water extract had no effect upon P4 secretion. Both alcohol/water and water extracted adrenal inhibited hCG secretion. The alcohol/water extract also increased P4 secretion, while the water extract had no effect. The alcohol/water and water extract liver had no effect upon hCG secretion. The effect of alcohol/water upon P4 secretion was markedly stimulatory, while the water extract had no effect. In conclusion, fetal visceral organs in very dilute concentrations have a significant effect upon placental hormonal secretion in vitro. In case of the lung, the active compound(s) appears to be a protein with a molecular weight of less than 8,000 daltons. The role of the human embryo in modulating early trophoblastic function is suggested.