Steroid metabolism of foetal tissues. V. Comparative studies in a 18 trisomic foetus.

After amniotic fluid and fetal skin biopsy cultures trisomy 18 was diagnosed and the steroid metabolism of tissues from this foetus was studied by double isotope methods and compared with results from foetuses of similar age. The metabolism of 14C-pregnenolone, the aromatization of androstendendione to oestrone and the 5alpha-reduction of testosterone to 5alpha-dihydrotestosterone in this foetus were similar as in other foetuses. The reason for a low oestriol excretion in pregnancy with 18 trisomic foetus is not evident from the data obtained.