Distribution and expression of GnRH 1, kiss receptor 2, and estradiol α and ß receptors in the anterior brain of females of Chirostoma humboldtianum

Abstract

Reproduction in vertebrates is a complex process regulated by many hormones, and by paracrine factors and their receptors. This study aimed to examine the expression of pjGonadotropin-releasing hormone (GnRH 1), the kisspeptin receptor 2 (kissr2), and estradiol receptors α and β (ER α and ER β) during different stages of the sexual cycle and their distribution within the anterior brain of females of Chirostoma humboldtianum. Among these molecules, the kissr2 showed the maximal variation in expression, while GnRH 1 showed minimal variation of expression, and ERβ and ERα had intermediate variation of expression. The distribution of these molecules in the anterior brain was consistent with their levels of expression; kissr2 was widely distributed throughout the telencephalon and diencephalon, while ER and GnRH 1 showed more restricted distributions. No coexpression of kissr2 and ER in GnRH 1ergic neurons, suggesting that regulation of this GnRH variant is indirectly mediated by kisspeptin and estradiol.

Effects of 17α-ethinylestradiol on the neuroendocrine gonadotropic system and behavior of European sea bass larvae (Dicentrarchus labrax)

“…Anyhow, there are contrasting results on the expression of ER in GnRH neurons in teleost, with co-expression found in some species as tilapia and medaka, but not in others as silverside or rainbow trout (Navas et al, 1995;Ogawa and Parhar, 2020;Macedo-Garzón et al, 2021). Furthermore, it is of interest to note that estrogen binding sites were detected in the promotor regions of the gnrh gene in zebrafish and sea bream, supporting the idea that estrogen can directly modulate GnRH expression (Torgersen et al, 2002;Hu et al, 2008).…”

Role of Habenula in Social and Reproductive Behaviors in Fish: Comparison With Mammals

“…In zebrafish, Kiss1 neurons in the vHb project their axons to the IPN via the fasciculus retroflexus, which terminate in the vaMR ( Nathan et al, 2015 ). In some fish species that possess only Kiss2, Kissr1 or Kissr2 is also expressed in the habenula ( Zmora et al, 2012 ; Ohga et al, 2017 ; Macedo-Garzón et al, 2021 ). In rodents, Kissr but not Kiss1 is expressed in the habenula ( Lee et al, 1999 ; Herbison et al, 2010 ; Simonneaux et al, 2013 ; Wagner et al, 2016 ).…”