Term decidua response to estradiol and progesterone

Immunoreactive prolactin (PRL) is produced from decidualized endometrium from the late luteal phase until the time of delivery. The induction of decidualization and the initiation of PRL production in the proliferative endometrium is dependent on progesterone (P) in vitro. This induction process is slowed by estradiol (E2). To determine whether this hormone dependency extends to term, decidua from labor and nonlabor term pregnancies was cultured in explant for response to P (100 ng/ml) and E2 (10 ng/ml) as evidenced by PRL production. On the first (n = 7) and eighth to ninth (n = 9) days of explant culture in nonlabor patients, P exposure resulted in significantly (p less than 0.01) more PRL production than in nonhormonal controls, and this increase was not inhibited by E2 at either time interval. In labor-exposed decidua, no significant response was noted to either P or E2 over 24 hours of culture. In all groups, tissue variability in PRL production was extensive. In nonlabor decidua, a significant interaction between basal PRL production and response to progesterone was noted (p less than 0.01). The role of P as an initiator and stimulator of PRL production extends to term; however, no clear effect of E2 is demonstrated. In labor-exposed decidua, this P response is eliminated. Whether this is a result of, or occurs prior to, labor is undetermined.