Induction of lordosis responsiveness by vaginal stimulation rats is independent of anterior or posterior pituitary hormones
Rodriguez-Sierra, J.F.; Crowley, W.R.; Komisaruk, B.R.
Hormones and Behavior 8(3): 348-355
1977
ISSN/ISBN: 0018-506X PMID: 881172 DOI: 10.1016/0018-506x(77)90008-3Document Number: 434554
In a previous study, rats that initially did not show lordosis in response to palpation of the flanks and perineum started to show lordosis to this stimulus when tested 10 s after brief vaginal stimulation and continued to show lordosis responsiveness for more than 3 h. In the present study, the possibility that this effect of vaginal stimulation is mediated by the release of pituitary hormones was tested. Hypophysectomized rats showed the lordosis-activating effect of vaginal stimulation, and this effect persisted for more than 1 h, similar to rats with intact pituitaries. Oxytocin (50 or 100 mU/rat) or vasopressin (100 mU/rat) injected systemically did not induce lordosis responding in ovariectomized rats that received either a single injection of estradiol benzoate (2 .mu.g/Kg) or no hormonal treatment. These individuals subsequently showed the lordosis-activating effect of vaginal stimulation. The mechanism by which vaginal stimulation activates lordosis responsiveness thus appears to be due to some process other than release of pituitary hormones.
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