INTERACTION BETWEEN OXYTOCIN AND PROSTAGLANDIN-F2-ALPHA IN HUMAN CORPUS-LUTEUM

The effect of a single injection of oxytocin into the corpus luteum, w ith or without pretreatment with a prostaglandin synthetase inhibitor, was studied in order to investigate possible local interactions betwe en prostaglandin (PG)F-2 alpha and oxytocin in the regulation of the h uman 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 cor pus luteum, or oxytocin was injected into the contralateral ovary. Oxy tocin injected into the corpus luteum caused a fall in serum progester one and shortened the luteal phase. These effects were not seen follow ing injection of saline into the corpus luteum, or following injection of oxytocin into the contralateral ovary. After the injection of oxyt ocin into the corpus luteum a rise in 15-keto-dihydro-PGF(2 alpha), a PGF(2 alpha), metabolite, was seen, The changes in serum progesterone caused by injection of oxytocin into the corpus luteum could be preven ted if a PG synthetase inhibitor was given before the injection. These findings suggest that local interaction between oxytocin and PGF(2 al pha) plays a role in the regulation of the human corpus luteum.