Quantification of androgens and their precursors in full-term human placenta

The two major androgens in humans are testosterone (T) and dihydrotestosterone (DHT). DHT is produced via the classical, backdoor, and alternative steroidogenic pathways. In addition, recent studies have identified C11-oxy C19 steroids as novel human androgens. Although the placenta is known to be involved in steroid metabolism, androgen levels in full-term placentas have poorly been investigated.

Ten placentas of healthy full-term neonates (five males and five females) were examined. We quantified progesterone, androstenedione (A4), T, allopregnanolone, androsterone, and estradiol, as well as four C11-oxy androgens (11β-hydroxyandrostenedione, 11β-hydroxytestosterone, 11-ketoandrostenedione (11KA4), and 11-ketotestosterone (11KT)), using liquid chromatography-tandem mass spectrometry.

In all samples, levels of the ten steroids were above the detection limit. Progesterone was by far most abundant, while levels of T and androsterone were relatively low. Levels of 11KT and 11KA4 were higher than those of T and A4, respectively. There were no differences in steroid levels between male and female samples.

This study demonstrates that full-term placentas contain several steroids in the classical, backdoor, and alternative pathways. Placentas are likely to function as the supplier of progesterone to other steroidogenic tissues. More importantly, we found that placentas comprise relatively large amounts of 11KA4 and 11KT, which may be produced through steroid transfer from the adrenal gland or from the maternal circulation. These results indicate that the placenta participates in a feto-maternal multi-organ network for androgen biosynthesis.