THE POSSIBILITY OF CORTICOSTEROID PRODUCTION BY HUMAN AND RAT PLACENTAL TISSUE UNDER IN VITRO CONDITIONS

Abstract

Human placentae obtained at Caesarean section were minced and incubated in vitro in Krebs–Ringer solution. The steroids secreted into the medium and those remaining in the tissue were measured.Seven ultraviolet light absorbing compounds were isolated from the incubation media. These included cortisone, hydrocortisone, progesterone, and four unidentified compounds. No detectable amounts of aldosterone, however, could be obtained from the quantities of tissue used.The amount of each steroid released into the incubation media decreased rapidly with time. An analysis of the original amount of each steroid present in the tissue before incubation indicated that no additional amounts of steroids were formed during the incubation periods. The addition of various steroid precursors such as progesterone, cholesterol, and Δ⁵-pregnene-3β-ol-20-one failed to increase the quantity of cortisone, hydrocortisone, or X₁, a compound with the same chromatographic mobility as aldosterone. Placental tissue has the ability to convert hydrocortisone to cortisone and also to reduce cortisone to hydrocortisone. This tissue is capable of converting cholesterol and Δ⁵-pregnene-3β-ol-20-one to progesterone, the latter precursor being at least 10 times more efficient than cholesterol in this respect.The addition of the trophic hormones ACTH, HCG, and prolactin did not stimulate the production of the measured steroids under the experimental conditions employed.Rat placental tissue did not secrete aldosterone, corticosterone, or any other Δ⁴-3-ketonic steroids of similar polarity in measurable amounts when incubated under in vitro conditions.