The brain is an important target organ for circulating steroid hormones secreted from peripheral organs such as the adrenal cortex, testis and/or ovary. In other words, these peripheral organs control the central nervous system. Steroid hormones substantially influence brain development, reproduction, sexual differentiation, cognition, memory, behavior, and so on. These effects are mediated by steroid hormone receptors, which directly regulate gene expression. The steroid hormone receptor superfamily is an intracellular ligand-regulated transcription factor. All members, including the glucocorticoid receptors (GR), mineralocoroticoid receptors (MR), estrogen receptors (ER), progesterone receptors (PR) and androgen receptor (AR), mediate the expression of a gene by binding to hormone responsive elements (HREs) as dimmers in a ligand-dependent manner. In particular, steroid hormones have an important role for the regulating neurons and cells, which are associated with the neuroendocrine and endocrine regulation system, because many neuroendocrine neurons and cells express the steroid hormone receptors, such as estrogen receptor (ER), androgen receptor (AR) and corticosteroid receptors. In this review, first the localization of GR and MR immunoreactivities in the brain is introduced, and secondly, the effects of change of GR expression in neurons are examined by several morphological approaches. Third, the interaction of GR expression and pituitary cell function is introduced. Finally, the recent topics on the control system of feeding regulation in the central nervous system, which also closely involves steroid hormone action, are discussed.

Background: Regulation of the reproductive system has been explained by the actions and feedback of gonadotropin releasing hormone‐luteinizing hormone/follicle stimulating hormone (GnRH‐LH/FSH) ‐sex steroids; however, the discovery of kisspeptin neurons and a kisspeptin‐GnRH‐LH/FSH axis has prompted this regulation to be reviewed.Methods: We investigated changes in kisspeptin neurons and associated changes in the hypothalamic‐pituitary‐gonadal (HPG) axis under various situations and experimental conditions using histochemical methods.Main findings (Results): Kisspeptin neurons play an important role in receiving and integrating information from internal and external environmental factors and communicating it to the conventional HPG axis.Conclusion: The recently described Kisspeptin‐GnRH‐LH/FSH‐gonad system regulates reproductive function via mechanisms that until recently were not completely understood.