| dc.description.abstract |
The common marmoset is a small New World primate that lives in extended familygroups. Female marmosets show rhythmic changes in proceptivity during their28-Day ovarian cycle, but fluctuations in sexual receptivity are relativelysubtle. Receptivity persists even after ovariectomy and adrenalectomy in thefemale marmoset. In the intact female, increases in proceptivity at mid cycleare due to the activational effects of oestradiol. Treatment of theovariectomized female with oestradiol-17&bgr;‚ stimulates proceptivityand this effect is blocked by thermal or excitotoxic (neuronal cell bodyspecific) lesions in the anterior or medial hypothalamus. Implantation ofoestradiol into the anterior hypothalamus (via guide cannulae) also activatesproceptivity. Luteinizing hormone releasing hormone (LHRH) may also form partof the neuroendocrine mechanism controlling proceptivity in the intact female,given that exogenous LHRH stimulates proceptivity in ovariectomized,oestrogen-primed marmosets. These effects of oestradiol (and LHRH) onproceptive displays are much more pronounced than any effects involving sexualreceptivity. Conversely, treatment of the ovariectomized female withprogesterone, at doses sufficient to produce luteal phase concentrations ofcirculating hormone, causes a marked suppression of proceptivity, but onlysmall decreases in sexual receptivity. These experiments on marmosets remainsome of the very few studies to define how hormones influence the brain andsexual behaviour in female primates. They support the conclusion that sexualreceptivity is not under rigid neuroendocrine control in female anthropoids,and that there is no peri-ovulatory period of oestrus, such as occurs in mostnon-primate mammals. |
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