Tumor necrosis factor in the human fetoplacentary unit.

In the present paper we review our findings on tumor necrosis factor (TNF) in human placental and adrenal tissues and suggest a possible novel biological role for this multi-functional lymphokine. TNF was found in the second and third trimester amniotic fluids in concentrations varying from 1.7 to 2.5 ng/ml on the average. In the amniotic fluid TNF was present in a biologically inactive form but in freshly-prepared supernatants of placental and decidual tissue homogenates corresponding levels were also found with bioassays based on the cytotoxicity of TNF to WEHI cells. In screening other fetal tissues we could detect biologically active TNF also in homogenates of fetal adrenals, and cultured fetal adrenal cells produced TNF upon stimulation with ACTH. A possible biological function for TNF was suggested by the findings that is suppressed the ACTH stimulated cortisol synthesis of fetal adrenal cultures and switched the steroidogenesis towards dehydroepiandrosterone (DHEA) and its sulphate (DHEAS). These are important precursors for placental steroid synthesis which are mainly provided by the fetal adrenals during normal gestation, and the results thus suggest a role for TNF in the regulation of steroidogenesis in the human fetoplacentary unit.