Effects of prostaglandins F-2α and E-2 on cervical extensibility in the late pregnant rat

摘要

Summary. The extensibility of the cervix of rats was measured in vitro on Day 19 of pregnancy and was doubled after 2 s.c. injections of PGF-2α (1 mg/kg) or PGE-2 (5 mg/kg) on Day 18. Progesterone (10 mg/kg) given on Day 18 had no effect alone or on the effect of PGE-2 but abolished the action of PGF-2α. PGE-2, but not PGF-2α, increased extensibility when given on Day 18 to rats which had been bilaterally ovariectomized on Day 16 and given oestradiol benzoate plus progesterone twice daily. High concentrations of PGF-2α or PGE-2 had no effect on the extensibility of Day-18 pregnant rat cervix in vitro. It is suggested that PGF-2α acts via the ovaries to decrease progesterone secretion and perhaps release relaxin, but PGE-2 would appear to have another site of action.