Endogenous neutral steroids in the lung tissue of early and mid-term human foetuses and in vitro studies on their formation.

Abstract

ABSTRACT Four pools of lung tissue from 2 or 3 foetuses of 11–17 weeks' gestational age were analyzed by gas-liquid chromatography and gaschromatography-mass spectrometry for endogenous neutral steroids. All of the steroids detected were present as their mono- or disulphate conjugates. No free compounds were found. Dehydroepiandrosterone, pregnenolone and their 16α-hydroxylated derivatives were the compounds present in highest concentrations in the monosulphate fraction. The most prominent steroid in the disulphate fraction was 5-androstene-3β,17α-diol. Other compounds detected were the monosulphates of 3β,7α-dihydroxy-5-androsten-17-one, 3β,16β- dihydroxy -5- androsten-17-one, 3β,17β- dihydroxy-5-androsten-16-one, 5-androstene-3β,16β,1 7α-triol, 5-pregnene-3β,17α-diol, and 3β,17α-dihydroxy-5-pregnen-20-one and the disulphates of 5-androstene-3β,17β-diol, 3β,16α-dihydroxy-5-androsten-17-one and 5-pregnene-3β,20α-diol. The total concentrations of steroids in the lung tissue varied from 300 to 600 μg/100 g tissue wet weight. In order to gain some insight into the origin of the endogenous steroids detected, i. e. whether they were synthesized by the lung tissue or only filtered by it from the perfusing blood, minced lung tissue was incubated with dehydroepiandrosterone, pregnenolone, 3β,17α-dihydroxy-5-pregnen-20-one and with their sulphate conjugates. Evidence for the presence of the following enzymes was found: sulphokinase, 7α-hydroxylase, 16αhydroxylase, 17α-hydroxylase, 17β-hydroxysteroid dehydrogenase, 20α-hydroxysteroid dehydrogenase and C17–20 desmolase.