[Changes in natural killer (NK) activity and fertility during the establishment of experimental endometriosis in the rat].

We examined the effect of experimental endometriosis (EE) on natural killer (NK) activities and fertilizability in the rat. EE was induced by autotransplantation of an endometrial fragment to the peritoneal wall. As a sham, abdominal fat tissue was implanted in the same way. NK activities of spleen cells were measured by means of a 4-hr 51Cr-release assay.(1) NK activities were significantly lower in EE than those in the sham (p < 0.001). (2) NK activity was recovered by surgical excision of the endometrial implant, but not increased by the administration of Danazol (100 mg/kg/day) or Buserelin (25 micrograms/kg/day) for 4 weeks. (3) The supernatant of endometriotic tissue cultures markedly suppressed NK activity. (4) The number of pups with EE was significantly smaller than in the controls (p < 0.05), but no difference between the two groups was observed in the number of oocytes in the Fallopian tube.(1) Splenic NK activity decreases at the time of the establishment of EE. (2) NK activity recovers after the removal of the implanted tissue. (3) Danazol and Buserelin have no effect on the NK activity in EE. (4) EE reveals some adverse effects on the postovulatory phase of fertility.