Presence of corticotropin in human placenta: demonstration of in vitro synthesis

Immunoassayable (I) and bioassayable (B) ACTH activity is present in extracts of extensively washed human placental tissue and dispersed viable trophoblasts (Tr). Similar concentrations (I) (1.7-2.7 ng/g) are present in term placentas from elective cesarian section or vaginal delivery and from plancentas obtained by prostaglandin-induced abortion at 12, 15 and 18 weeks of gestation. Oral dexamethasone (8-12 mg) administered over an 8-48 h period prior to delivery does not significantly alter placental ACTH content. B-ACTH concentrations are 31-40% of I-ACTH. Sephadex G-50 filtration of term placental homogenates demonstrates two I-ACTH peaks, one eluting in the void volume and the other eluting in the region of synthetic hACTH1-39. When Tr are incubated in tissue culture medium, ACTH content of cells and of medium is significantly greater than pre-incubation levels.