Actions of sex steroids on kisspeptin expression and other reproduction-related genes in the brain of the teleost fish European sea bass
|Author(s)||Alvarado M. V.1, Servili Arianna2, Moles G.1, Gueguen M.M.3, Carrillo M.1, Kah O.3, Felip A.1|
|Affiliation(s)||1 : CSIC, Grp Fish Reprod Physiol, Dept Fish Physiol & Biotechnol, Inst Acuicultura Torre Sal S-N, Ribera De Cabanes 12595, Castellon, Spain.
2 : IFREMER, LEMAR UMR 6539, Unite Physiol Fonct Organismes Marins, BP 70, F-29280 Plouzane, France.
3 : Univ Rennes 1, INSERM U1085, Res Inst Hlth Environm & Occupat, Campus Beaulieu, F-35042 Rennes, France.
|Source||Journal Of Experimental Biology (0022-0949) (Company Of Biologists Ltd), 2016-11 , Vol. 219 , N. 21 , P. 3353-3365|
|WOS© Times Cited||11|
|Keyword(s)||kiss1/kiss2, gnrh-1/gonadotropin, Feedback action, Sex steroid, Hypothalamus, Perciform|
|Abstract||Kisspeptins are well known as mediators of the coordinated communication between the brain-pituitary axis and the gonads in many vertebrates. To test the hypothesis that gonadal steroids regulate kiss1 and kiss2 mRNA expression in European sea bass (a teleost fish), we examined the brains of gonad-intact (control) and castrated animals, as well as castrated males (GDX) and ovariectomized females (OVX) that received testosterone (T) and estradiol (E2) replacement, respectively, during recrudescence. In GDX males, low expression of kiss1 mRNA is observed by in situ hybridization in the caudal hypothalamus (CH) and the mediobasal hypothalamus (MBH), although hypothalamic changes in kiss1 mRNA levels were not statistically different among the groups, as revealed by real-time PCR. However, T strongly decreased kiss2 expression levels in the hypothalamus, which was documented in the MBH and the nucleus of the lateral recess (NRLd) in GDX T-treated sea bass males. Conversely, it appears that E2 evokes low kiss1 mRNA in the CH, while there were cells expressing kiss2 in the MBH and NRLd in these OVX females. These results demonstrate that kisspeptin neurons are presumably sensitive to the feedback actions of sex steroids in the sea bass, suggesting that the MBH represents a major site for sex steroid actions on kisspeptins in this species. Also, recent data provide evidence that both positive and negative actions occur in key factors involved in sea bass reproductive function, including changes in the expression of gnrh-1/gonadotropin, cyp19b, er and ar genes and sex steroid and gonadotropin plasma levels in this teleost fish.|