Interaction between oxytocin and prostaglandin F2 alpha in human corpus luteum?

The effect of a single injection of oxytocin into the corpus luteum, with or without pretreatment with a prostaglandin synthetase inhibitor, was studied in order to investigate possible local interactions between prostaglandin (PG)F2 alpha and oxytocin in the regulation of the human corpus luteum. Oxytocin (4 IU) was injected through the abdominal wall into the corpus luteum in women undergoing laparoscopy for legal sterilization. In the control cases, saline was injected into the corpus luteum, or oxytocin was injected into the contralateral ovary. Oxytocin injected into the corpus luteum caused a fall in serum progesterone and shortened the luteal phase. These effects were not seen following injection of saline into the corpus luteum, or following injection of oxytocin into the contralateral ovary. After the injection of oxytocin into the corpus luteum a rise in 15-keto-dihydro-PGF2 alpha, a PGF2 alpha metabolite, was seen. The changes in serum progesterone caused by injection of oxytocin into the corpus luteum could be prevented if a PG synthetase inhibitor was given before the injection. These findings suggest that local interaction between oxytocin and PGF2 alpha plays a role in the regulation of the human corpus luteum.