PROGESTERONE, 20α-DIHYDROPROGRESTERONE AND 20β-DIHYDROPROGESTERONE LEVELS IN DIFFERENT COMPARTMENTS FROM THE HUMAN FOETO-PLACENTAL UNIT

ABSTRACT The endogenous levels of progesterone, 20α-dihydroprogesterone and 20β-dihydroprogesterone in different foetal tissues, in placental tissue and in foetal blood during pregnancy (week 9–25) were determined by gas-liquid chromatography or by radioimmunoassay. The identification of these steroids in foetal tissues was based on the behaviour in paper and thin-layer chromatography, the formation of different derivatives, and the retention times in gas-liquid chromatography. For additional identification of progesterone and 20α-dihydroprogesterone a mass spectrum was obtained. The average concentrations of progesterone (P), 20α-dihydroprogesterone (20α-DHP) and 20β-dihydroprogesterone (20β-DHP) in foetal tissues were as follows (ng/g wet weight tissue): brain, P 119.0 ± 45.5, 20α-DHP 86.9 ± 44.7 and 20β-DHP 9.7; lungs, P 257.7 ± 195.7, 20α-DHP 60.3 ± 26.4 and 20β-DHP 7.8; liver, P 103.7 ± 84.6, 20α-DHP 95.2 ± 89.8 and 20β-DHP 17.8; adrenals, P 295.7 ± 90.0 and 20α-DHP 254.5 ± 194.6; kidneys, P 214.2 ± 155.3 and 20α-DHP 76.6 ± 43.0; intestine, P 273.2 ± 166.7, 20α-DHP 77.9 ± 51.2 and 20β-DHP 8.7; residual tissues, P 246.3 ± 178.3 and 20α-DHP 54.8 ± 44.5 The average concentrations in placental tissue and in foetal plasma (week 12–18) were as follows (ng/g wet weight tissue or ng/ml plasma): placenta, P 2619. ± 2153.6 and 20α-DHP 461.0 ± 155.9; foetal plasma, P 378.7 ± 231.8 and 20α-DHP 283.0 ± 108.9 These results indicate that some foetal organs contain a high 20α-reductase activity at least during the first half of pregnancy.