Pharmacological activity of PGI2 and its metabolite 6-oxo-PGF1alpha on human uterus and fallopian tubes

Abstract

The actions of prostacyclin (PGI2) and its stable metabolite 6-OXO-PGF1alpha were investigated in strips of normal human uterus and in fallopian tubes. Both compounds were also compared with natural prostaglandins (PGE2, PGF2alpha and PGD2). PGI2 showed biphasic response both in uterus and fallopian tubes qualitatively and quantitatively similar to that induced by PGE2 and PGD2; prostacyclin was also able to inhibit the spasmus induced by PGF2alpha but not that induced by BaCl2 and vasopressin. 6-0XO-PGF1alpha on the other hand induced only small contractions on both tissues investigated. The authors discusse the possible implication of these findings in the physiology of the reproductive system.

PIP: To obtain more information on the importance of prostacyclin (PGI2), and of its stable metabolite 6-oxo-PGF1, in the maintenance of uterine and placental circulation, their pharmacological activity was studied on strips of nonpregnant human uterus and human fallopian tubes, and compared with the action of natural prostaglandins PGE2, PGF2 and PGD2. Prostacyclin induced a biphasic response on strips of uterus and of fallopian tubes; in 6 different experiments an initial contraction followed by relaxation associated with loss of spontaneous motility was constantly observed in a dose dependent manner; PGE2 and PGD2 also inhibited the spasmus induced by PGF2, but not that induced by BaCI2 and vasopressin. The contractions caused by 6-oxo-PGF1 on both uterine and fallopian tube strips were considerably less potent. These experiments clearly demonstrate that PGI2 interferes with spontaneous motility of tonus of the normal uterus. It must be underlined that the effect of PGI2 and of 6-oxo-PGF1 is species dependent, since in rat uterus, unlike in the human uterus, both compounds induce contractions.