IS HUMAN LABOR TRIGGERED BY AN INCREASE IN THE RATE OF SYNTHESIS OF PROSTAGLANDIN-G/H SYNTHASE

The increase in the synthesis of prostaglandins by intrauterine tissues which occurs at the time of parturition may be the consequence of periparturient changes in several regulatory pathways. The aim of this study was to determine whether changes in the rate of synthesis of prostaglandin G/H synthase (PGHS) contribute to the labour-associated increase in prostaglandin synthesis by human chorioamnion and placenta. The rate of recovery of prostaglandin E2 (PGE2) synthesis following inhibition of PGHS by aspirin was used as an estimation of PGHS resynthesis. In tissues obtained following spontaneous delivery, the half-time recovery of PGE2 synthesis was 3’5 to 6-0-fold less (P< 0-001; n = 5) than the half-time recovery observed in tissues obtained before the onset of labour. These data suggest that a periparturient increase in the rate of synthesis of PGHS contributes to enhanced prostaglandin synthesis at term. © 1990 CSIRO. All Rights Reserved.