Pronucleus formation following in vitro fertilization of oocytes recovered from a gorilla (Gorilla gorilla gorilla) with unilateral endometrioid adenocarcinoma of the ovary.

A 33-year-old, nonreproductive female gorilla was scheduled for ovariohysterectomy after diagnosing endometrioid adenocarcinoma of the right ovary; the contralateral ovary appeared small and inactive. Follicular recruitment and maturation were stimulated on the left ovary using human menopausal gonadotropin and human chorionic gonadotropin therapy. Three oocytes were recovered and inseminated using a thawed epididymal semen sample collected postmortem and cryopreserved. At 18 h postinsemination, one ovum was fertilized, the second showed evidence of polyspermia, and the third was unfertilized; no further embryonic development was observed. These results demonstrate that viable oocytes can be salvaged from a nonreproductive gorilla using a human exogenous gonadotropin treatment protocol and fertilized in vitro using cryopreserved/thawed epididymal gorilla semen.