Wallig, in Fundamentals of Toxicologic Pathology (Second Edition), 2010 Sex Hormones and Hormone Receptors Sex hormones exert their action on neurons either by changes in gene expression or by regulating membrane excitability through their own membrane receptors, as well as via direct action at neurotransmitter receptors and ion channels. Since the brain is a sexually dimorphic structure, it is not surprising that the effects of sex hormones on neuronal excitability are sex-specific. This profound hormonal decline is associated with alterations in seizure pattern or even onset of new seizures. Another significant factor in women is the loss of peripheral source of sex hormones at menopause. Hormonal fluctuations during the menstrual cycle mark the catamenial occurrence of seizures in some women. The hormone-related disorders can occur in both sexes but are mostly studied and best characterized in women due to dramatic changes in their hormonal state throughout the lifespan. Hormone-induced changes in neuronal activity are believed to be an underlying mechanism for several disorders, such as migraine, depression, schizophrenia or epilepsy (eg, catamenial epilepsy). Sex hormones influence neuronal excitability, depending on the hormone type or its metabolite. Velíšek, in Reference Module in Neuroscience and Biobehavioral Psychology, 2017 Introduction However, it is important to note that sex steroid effects on immune cells are likely dependent on steroid concentration, timing, duration, and context of exposure. Women usually show greater humoral responses, but in men both humoral and cell-mediated immune responses are relatively suppressed by sex steroids. Increased female prevalence for autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis), and a higher ratio for allergic asthma in females collectively suggest that female sex hormones could play a major role in immunologic airway inflammation. Sex differences in immune responses and their regulation have been reported in several studies. Sex steroids are thought to be involved in regulating multiple immune cells such as dendritic cells, lymphocytes, regulatory T-cells, and B lymphocytes, all of which may be relevant to lung function, particularly in the context of recruitment of immune cells in asthma and modulating of the inflammatory environment. Prakash, in Sex Differences in Physiology, 2016 Sex Steroid Effects in Immune Cells A more thorough understanding of the mechanisms mediating sex hormone–related neural function and dysfunction should facilitate the refinement of rational hormonal and antihormonal therapies for many of the conditions discussed in this chapter. The ubiquitous nature of these interactions warrants routine inquiry into potential symptom modifications associated with the menstrual cycle, pregnancy, menopause, and hormonal contraceptive exposure in women with neurological and psychiatric illness. Fluctuating sex hormone levels also influence the expression of certain neuropsychiatric states and neuroendocrine disorders. In other diseases, including such diverse entities as primary CNS neoplasms and various movement disorders, this relationship has not been confirmed but appears likely in the light of rapidly accumulating clinical, epidemiological, and biochemical data. Relationships between endogenous and exogenous sex hormones and many neurological conditions, such as migraine, stroke, and chorea, are well established. Sex hormones influence a broad spectrum of normal and abnormal neurological functions. Schipper, in Neurology and General Medicine (Fourth Edition), 2008 CONCLUDING COMMENTS