Estrogen accelerates the recovery of the lordosis response after its exhaustion induced by cervical probing.

Repetitive flank-perineum palpation combined with probing the vaginal cervix in ovariectomized hormonally untreated rats elicited a mean of 4.2 +/- 0.2 (SEM) successive lordosis responses before the response was exhausted. Two days after a single injection of estradiol benzoate (100 micrograms/kg body wt) in ovariectomized rats, a significantly greater number (7.8 +/- 0.2) of lordosis responses could be elicited before the response was exhausted (P less than 0.01). After this exhaustion, recovery of lordosis responsiveness to this stimulation occurred significantly earlier in the estrogen-treated rats (6 hr) than in the oil-treated rats (60 hr) (P less than 0.01). Several possible mechanisms mediating these effects are proposed.