A preliminary study of prostaglandin release by bradykinin (BK) on isolated human myometrium

The aim of this study was to investigate whether the response to BK on isolated human myometrium from non-pregnant (NP) and pregnant (P) donors involves the release of prostaglandin I2 (PGI2) and/or of PGE2. BK was injected as a bolus dose into the flow of the superfusate. The perfusate was collected during a response to BK and PG concentration measured by enzymoimmunoassay for PGE2 or PGI2. The BK response was biphasic, consisting of contraction followed by inhibition of myogenic activity. In tissues from both NP and P donors BK was found to cause a dose related release of PGE2 and PGI2. BK evoked PGE2 release which was greater during the contractile response than in the inhibitory response. Following the same dose of BK, PGI2 release was found to be greater in the inhibitory response than in the contractile phase. The findings indicate that in isolated human myometrium the response to BK does involve the release of PGE2 and PGI2 and in both NP and P tissue PGE2 release is greater in the contractile response phase whilst PGI2 predominates the inhibitory phase.