The Actions of Prostaglandins and the Interactions of Angiotensin II in the Isolated Perfused Human Placental Cotyledon
Several lines of evidence suggest that in the fetal-placental circulation, the vasoconstrictive actions of angiotensin II may be modulated by prostaglandins. Firstly, prostaglandins have been shown to be vasoactive within the fetal-placental vaculature (Tulenko 1981; Mak et al., 1984). Secondly, angiotensin II is able to stimulate the release of PGE and prostacyclin (PGI2) (a potent vasodilator) into the fetal circulation of the isolated perfused human placental cotyledon (Glance et al., 1985). Thirdly, in pathological pregnancies where umbilical blood flow is reduced (such as pre-eclampsia [Makila et al., 1983]), circulating fetal angiotensin II levels are increased (Broughton Pipkin and Symonds, 1977) and PGI2 levels are decreased (Makila et al., 1983) when compared with levels found in normal pregnancies.
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- Broughton Pipkin, F. and Symonds, E.M. (1977) Factors affecting angiotensin II concentrations in the human infant at birth. Clin. Sci. Mol. Med. 52, 449–456.Google Scholar