title: Evidence for progesterone synthesis by human umbilical cord blood erythrocytes.
abstract: In order to determine whether human umbilical cord blood erythrocytes are capable of progesterone biosynthesis, sonicated preparations of plasma-free erythrocytes at the range of total cell numbers between 18.4 x 10(9) and 62.9 x 10(9) cells obtained from umbilical cord arterial and venous blood collected from normal pregnant women (n = 6, age 28-39 years) following spontaneous vaginal delivery were incubated with [7n-(3)H]-pregnenolone as substrate. The leucocyte content of the incubates was negligible (<0. 005%). Controls (n = 4, age 29-36 years; 27.6 x 10(9) to 42.7 x 10(9) erythrocytes) obtained from cord blood of normal pregnant women were heat-denatured preparations of cells. Using the reverse-isotope dilution technique, [(3)H]-progesterone was isolated and characterized yielding an overall enzymic conversion which ranged between 0.27 and 0.46%. The results indicate for the first time that cord blood erythrocytes possess the 3beta-hydroxysteroid dehydrogenase-5,4-en isomerase activity and are a source of progesterone in human pregnancy.
authors.affiliation: University Department of Obstetrics and Gynaecology, National University Hospital, Singapore.
authors.forename: A
authors.initials: A
authors.lastname: Loganath
authors.forename: K L
authors.initials: KL
authors.lastname: Peh
authors.forename: P C
authors.initials: PC
authors.lastname: Chew
authors.forename: Y C
authors.initials: YC
authors.lastname: Wong
authors.forename: S C
authors.initials: SC
authors.lastname: Ng
mesh_terms: D000328:Adult; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D011247:Pregnancy; D011284:Pregnenolone / Q000097:blood; D011374:Progesterone / Q000096:biosynthesis* / Q000097:blood; D014316:Tritium
chemical_list: D014316:Tritium; D011374:Progesterone; D011284:Pregnenolone