Pregnanolones and pregnenolone in human myometrium at term of pregnancy.

Abstract A gas choromatographic method was developed for the separation and quantitative determination of the epimers of pregnanolones (3α/β-hydroxy-5α/β-pregnan-20-ones), pregnenolone and the sulfoconjugated steroids in small biological samples. The reliability and sensitivity of the method (1–2 ng of steroid) was sufficient to permit the determination of these steroids in human uterine tissue obtained at term of pregnancy. Mean concentration of the free steroids were 10–19 ng/g tissue. The sulfoconjugated steroids were found to have mean levels of 13–32 ng/g. A significant difference of concentrations was observed between free and sulfoconjugated 3α-hydroxy-steroids. This was not found to be the case with the 3β-hydroxy-steroids. The results suggest that these compounds may originate only in part from progesterone metabolism within uterine tissue.