Intra-uterine tissues from late-pregnant rhesus monkeys (Macaca mulatta) produce 6-oxo-prostaglandin F1 alpha in vitro.

The rates of production of 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha) in vitro by intra-uterine tissues taken from late-pregnant monkeys at Caesarean section have been determined. For tissues obtained between days 140 and 149 of pregnancy (late pregnancy) the general quantitative order of rates of production (per unit weight) was decidua basalis greater than placenta greater than decidua parietalis greater than amnion greater than chorion = myometrium. When tissues were taken between days 160 and 168 of pregnancy (near term) this order was placenta greater than decidua parietalis = amnion greater than myometrium = decidua basalis greater than chorion. There was a significant reduction near term in the rate of production of 6-oxo-PGF1 alpha by decidua basalis; all other tissues exhibited similar rates of production at the two gestational periods investigated.