In vitro production of prostaglandins E, F, and 6-keto prostaglandin F1 alpha by human pregnant uterus, decidua and amnion.

The production of prostaglandins (PGs) E and F and 6-keto PGF1 alpha was investigated by using human decidua, amnion, and pregnant myometrium obtained before and after onset of labor, and human nonpregnant myometrium collected during luteal phase. PGs produced were measured by radioimmunoassay developed in our laboratory. The radioimmunoassay for 6-keto PGF1 alpha is specific and accurate. PGE was formed at an almost constant rate regardless of the condition under which the three tissues tested were obtained, with the amnion showing the highest activity compared with decidua and myometrium. PGF production increased remarkably during labor in the myometrium and decidua but not in the amnion. In the myometrium during labor, PGF levels were three times higher than before labor. The pregnant myometrium produced more PGs than the nonpregnant myometrium. The production of 6-keto PGI1 alpha, a stable, non-enzymatically formed derivative of PGI2, was observed to be much higher in the pregnant myometrium than in decidua, amnion, or nonpregnant myometrium. Contrary to the pattern of PGF production, 6-keto PGF1 alpha was lower during labor. The physiological significance of PG production by decidua, amnion, and myometrium in relation to parturition is discussed.