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Steroid Implants in the Medial Preoptic Area or Ventromedial Nucleus of the Hypothalamus Activate Female Sexual Behaviour in the Musk Shrew
Author(s) -
Veney S. L.,
Rissman E. F.
Publication year - 2000
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1046/j.1365-2826.2000.00567.x
Subject(s) - medicine , endocrinology , testosterone propionate , ventromedial nucleus of the hypothalamus , stria terminalis , hypothalamus , testosterone (patch) , preoptic area , biology , lordosis behavior , androgen , hormone , ovariectomized rat , estradiol benzoate
Female musk shrews are induced ovulators that do not exhibit a spontaneous behavioural oestrous cycle. Testosterone produced by the ovaries and adrenal glands, is the major steroid hormone in circulation at times of mating, and as such, regulates sexual behaviour. In the first experiment, we identified the neural site(s) of action for testosterone. Hormone implants were placed in one of three targeted brain regions. The neural sites selected were the medial anterior division of the bed nucleus of the stria terminalis (BNSTMA), medial preoptic area (mPOA) and the ventromedial nucleus of the hypothalamus (VMN). Ovariectomized females who received a unilateral testosterone propionate implant in either the mPOA or VMN, were significantly more likely to display sexual behaviour as compared to females who received an implant in the BNSTMA or any other hypothalamic nucleus. In experiments 2 and 3, we investigated whether the behavioural effects of testosterone propionate were mediated by an oestrogen receptor or the androgen receptor. Ovariectomized females that received oestradiol (E 2 ) implants in either the mPOA or VMN were more likely to display receptivity, and had significantly shorter behavioural latencies, as compared to females implanted with either dihydrotestosterone or cholesterol. These data show that neural aromatization of testosterone to E 2 in the mPOA or VMN is necessary for optimal activation of female musk shrew sexual behaviour. This finding implies a degree of neural redundancy in the networks that control the expression of sexual receptivity.