Prolactin synthetizing capacity of the human decidua during the first trimester of pregnancy.

In vitro prolactin (PRL) synthesis by human decidua of early pregnancy (5-12 weeks gestation) was investigated. Tissues obtained during therapeutic abortions were incubated in oxygenated Gey's buffer supplemented with 20% fetal calf serum at 37 degrees C for 24 h. PRL production increased rapidly to 42.3 mU PRL/100 mg tissue wet weight until 8 weeks gestation and then slightly declined but these differences were not significant. There was not PRL production when chorion was incubated under similar conditions. A significant correlation was found when the initial PRL content in the decidua prior to incubation and the capacity of decidua to synthesize PRL were compared (r = 0.76, P less than 0.001). These data provide further evidence that human decidua can produce PRL in vitro. The finding that the rate of the PRL synthesis increases progressively in early pregnancy is in correlation with the intensive decidualization of the endometrium.