SUMMARY
[4-14C]Progesterone was injected into the umbilical vein of two pre-viable human foetuses. The first was dissected 14 min. after injection and the second perfused for 45 min. and then dissected. All tissues of the second foetus and the liver and adrenals of the first were examined for the presence of radioactive metabolites. Most of the steroids were present in free form, 91% and 92·5% in the liver, and 81·5% and 77% in the adrenals of the first and second foetuses, respectively. The main free steroid in the liver at 14 min. was 20α-hydroxypregn-4-en-3-one (36% of the total free steroid extracted from the liver), whereas at 45 min. it was 5β-pregnane-3α,20α-diol (69%). In the adrenals in both experiments radioactivity was present in polar compounds, 47% at 14 min. and 60% at 45 min.
The heart in the human foetus
