To determine the range of responses in ovarian steroid secretion to PMSG treatment, ovarian steroid secretion rates and circulating FSH concentrations were studied in ewes with ovarian autotransplants following treatment with or without PMSG (400 IU) during the breeding season and anestrus. The ewes were treated with progestagen pessaries for 12 d. A prostaglandin analogue (PG) was administered at the time of pessary withdrawal to induce luteolysis (0 h). The PMSG was also administered at 0 h. Jugular and ovarian venous blood samples were taken at 10-min intervals at 2 stages (21 to 27 h and 38 to 42 h post PG). There was no change in peripheral plasma FSH concentrations in control ewes with a change in season. Mean peripheral plasma FSH concentrations decreased in PMSG-treated ewes relative to controls in both the breeding season and seasonal anestrus (P < 0.01). Treatment with PMSG increased the ovarian androstenedione and estradiol-17β secretion rates relative to that of the controls in both the breeding season and seasonal anestrus (P < 0.05). The rate of estradiol-17β secretion in PMSG-treated ewes was lower in seasonal anestrus than in the breeding season (P < 0.05). There was a greater range in ovarian steroid secretion response between PMSG-treated individuals, which was most apparent during seasonal anestrus.