Kisspeptin
a neuropeptide encoded by Kiss1 gene
plays pivotal roles in the regulation of reproductive function. Recently various stressors and stress-induced molecules such as corticotropin-releasing hormone (CRH) and corticosterone have been shown to inhibit Kiss? expression in rat hypothalamus. To determine whether CRH and glucocorticoids directly act on kisspeptin neurons
we examined the colocalization of CRH receptor (CRH-R) and glucocorticoid receptor (GR) in kisspeptin neurons in the female rat hypothalamus. Double-labeling immunohistochemistry revealed that most kisspeptin neurons in the anteroventral periventricular nucleus and periventricular nucleus continuum (AVPV/PeN)
and arcuate nucleus (ARC) expressed CRH-R. We also observed a few close appositions of CRH immunoreactive fibers on some of kisspeptin neurons in AVPV/PeN and ARC. On the other hand
most kisspeptin neurons in AVPV/PeN expressed GR
whereas only a few of kisspeptin neurons in ARC expressed GR.Altogether
our study provides neuroanatomical evidence of the direct modulation of kisspeptin neurons by CRH and glucocorticoids and suggests that stress-induced CRH and glucocorticoids inhibit gonadotropin secretion via the kisspeptin system. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
