Synthesis and metabolism of prostaglandins in rat placenta, uterus, and ovary during various stages of pregnancy.

1. In the rat, during days 8 to 21 of pregnancy there exists distinct patterns for prostaglandin synthesis and metabolism in the placenta, uterus, and ovaries. These patterns are different in each of the organs. 2. The ratios between PGF and PGF2alpha synthesized or metabolized changes for each of the reproductive tissues studied. 3. Day 11 of gestation represents a critical period as reflected by a highly elevated synthesis and metabolism of prostaglandins. 4. Uterine prostaglandin synthesis increases progressively during the last trimester of pregnancy being maximal on the day of parturition.