Ovine placental cortisol production.

Cortisol levels were determined by radioimmunoassay in samples simultaneously obtained from the four vessels serving the ovine placenta (uterine artery and vein, umbilical artery and vein). These samples were collected daily over a 20- to 30-day interval in three animals in the latter third of pregnancy. Cortisol levels in the uterine and umbilical veins were higher than those in the arteries in 67 of 73 sample sets. Net synthesis of 11-deoxycortisol and cortisol from 17 alpha-hydroxyprogesterone by dispersed placental cells was also demonstrated in vitro. These data provide strong evidence that the ovine placenta has the ability to synthesize 11-deoxycortisol and cortisol in vitro and normally does so in vivo.