Effects Of Chronic Tamoxifen Treatment In The Hypothalamic Circuitry That Regulates Female Sexual Behaviour

Abstract

Introduction: The medial preoptic (MPN) and the ventromedial hypothalamic nuclei (VMN) are hypothalamic areas that control the proceptive and the receptive component, respectively, of the female sexual behavior. This behavioral response is dependent on the activation of estrogen (ER) and progesterone receptors (PR). Tamoxifen (TAM) is a modulator of the steroid receptor activation and previous studies have shown that it inhibits female rodent sexual behavior and that women taking TAM complain about diminished libido. However, the mechanisms underlying this event are currently unknown. For decades, TAM has been used as an anti-estrogen in estrogen-dependent breast cancer (BC) treatment while endocrine therapies have improved the clinical outcomes of this disease. Nowadays it is offered a 5-year prophylactic TAM therapy to woman with high risk of having BC. Therefore, the impact of endocrine therapy on the quality of life is extremely important. Objective: With the identification of the effects of long-term TAM therapy in the structural and biochemical plasticity of the MPN and the VMN, this study aimed to improve the knowledge about the behavioral outcomes associated with TAM therapy.