Changes in myometrial and placental 15-hydroxyprostaglandin dehydrogenase with ovine parturition: production of prostaglandin metabolites in vitro and in vivo.

15-Hydroxyprostaglandin dehydrogenase (PGDH) was measured in vitro in myometrium and maternal cotyledons from 6 sheep and in fetal cotyledons from 3 sheep before and after parturition. Maternal cotyledons contained more PGDH than fetal cotyledons or myometrium. At parturition, PGDH activity decreased in myometrium but increased in fetal and maternal placental tissue. The enzymatic activity observed in vitro did not result in a large, consistent release of prostaglandin F metabolites into the utero-ovarian vein in vivo, and such activity may have a strictly localized effect in ovine parturition.