The effect of hysterectomy on hormone-induced lordosis behavior in hamsters

Ovariectomized-hysterectomized (OH) and ovariectomized-sham hysterectomized (OSH) hamsters were tested for lordosis behavior following treatments including either 1, 5, or 10 micrograms estradiol benzoate (EB) in combination with 0.1, 0.25, and 0.5 mg progesterone. Few animals responded at the 1 microgram dose of EB and there were no differences in latency to the first display of lordosis or in the total lordosis duration among responding animals in the 5 and 10 micrograms EB groups. However, there was significantly more positive tests in the OSH group injected with 5 micrograms EB than in the OH group and this difference approached statistical significance in the 10 micrograms EB groups. The results are compared to similar studies in rats and possible mechanisms for the effects of hysterectomy are discussed.