Regionally different stetoid-biosynthesis within materno-fetal circulation units (placentones) of mature human placentas

Abstract

Earlier studies [8] demonstrated the morphological differences between chorionic villi of central and peripheral regions in placentones. Histochemical and biochemical investigations [9] revealed results corresponding to the morphological findings, that is regionally difFerentiated activity of alkaline phosphatase. They showed that centrally situated villi, which demonstrate a lower degree of maturity than peripherally situated ones, also reacted like less mature villi in respect to activity of alkaline phosphatase. The purpose of this paper is to examine whether enzymes of steroid-biosynthesis also demonstrate regional differences concerning their own specific activities. This concerns, above all, aromatising enzyme Systems and 17ß-hydroxysteroid-oxidoreductase. For this reason, we measured the in vitro transformation of 2d-4-androstendione to testosterone and to oestrone/oestradiol-17j8 by microsomes fromtissue of central and peripheral regions of the placentone. Material and Methods TissueEight placentas were used from clinically uncomplicated pregnancies, which ended in spontaneous deliveries between the 38th and 40th weck of pregnancy. Weight of newborns was normal, ApGAR-scores were never under 9. Germany. 1961 Medical Doctor. 1963-1966 Membranes and blood were removed immediately post partum and placentas were cut into 2 cm wide sections vertically to the maternal surface. With the help of a dissecting lens we took biopsies from .central ^ad.,peripheraLareas-of •plaGentones^ekuäted in the middle portion of the placenta. Tissue was then homogenized in 0.25 M sucrose in a glass homogenisator. (The method has been described elsewhere [5].) Remains of connective tissue which coüld not be homogenized were * Investigations were supported by the Forschungsgemeinschaft". "Deutsche J. Perinat. Mcd. l (1973) Curriculum vitae WOLF DIETRICH LEHMANN, M. D. born in 1935 in Kielj

Architecture of Normal Villous Trees

“…Whereas the centers act as proliferative zones that guarantee placental growth until term, the periphery is the functionally fully active exchange and secretory area. This situation has also been highlighted by the histochemically and biochemically higher activity of enzymes such as alkaline phosphatase (Schuhmann et al, 1976) and by the higher conversion rate of steroid hormones (Lehmann et al, 1973) in the placentone periphery.…”