The neuroendocrine integration is fundamental for the regulation of several important physiological processes such as homeostasis, osmolarity, metabolism and energy balance, and motivated behaviors such as feeding and drinking, aggression and reproduction. Ovarian hormones, namely estradiol and progesterone, are released in a cyclic mode and have a crucial role in the modulation of the neuronal component of the neuroendocrine system. Therefore, study of the intrinsic mechanisms involved in the regulation of this axis is pivotal for the knowledge of physiological processes. The cyclic secretion of ovarian hormones is essential for the maintenance of female neuroendocrine regulation in a way that its dysregulation, either natural or pathological, will affect almost all physiological processes. The experimental models that can be used to study the effects of estrogens and/ or progestins may target the action of the hormones, by relying on the natural cycling female or by external administration of estradiol and/ or progesterone to females without ovaries. Contrariwise, such models may target the activation of individual estradiol and progesterone receptors, using agonists and antagonists of its action. The experimental models of Tamoxifen administration rely on the knowledge that it is a selective estrogen receptor modulator (SERM) and has been widely used as a therapy for the estrogen-dependent breast cancer. Knowing how tamoxifen acts in the neuroendocrine regulation of physiological processes can provide relevant clues to understanding estrogen receptor modulation and the possible side effects of such a therapy.