| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5900910 | General and Comparative Endocrinology | 2015 | 13 Pages |
â¢Expression changes of mRNAs were analyzed during early development and gonadal sex differentiation.â¢Expression of kiss, kissr, and gnrh mRNAs varied during early development and gonadal sex differentiation.â¢Expression of kiss, kissr, and gnrh mRNAs in different brain regions showed regional differences.â¢First report on expression of kisspeptins and their receptors during gonadal sex differentiation.
In recent years, brain kisspeptin system has been shown to be involved in diverse reproductive function, including sexual differentiation in vertebrates. Our previous reports demonstrated that the chub mackerel (Scomber japonicus) brain expresses two kisspeptin (kiss1, kiss2), two kisspeptin receptor (kissr1, kissr2) and three gonadotropin-releasing hormone (gnrh1, gnrh2, gnrh3) genes. In the present study, using quantitative real-time PCR (qRT-PCR) assays, we analysed expression changes of these genes during early development (0-30Â dphs) and gonadal sex differentiation periods (37-60Â dphs). Absolute expression level of kiss-kissr-gnrh in the whole head was higher between 0 and 15Â dphs, in comparison to later developmental periods. Histological analyses revealed presence of sexually differentiated males and females with testicular and ovarian features at 37, 45, and 60Â dphs. In both males and females, kiss2, kissr1, and kissr2 levels were higher at 37Â dph, in comparison to 45 and 60Â dphs, with kiss1 showing no significant differences. Levels of all three gnrh mRNAs were higher at 45Â dph, in comparison to 60Â dph. Changes in the expression level of kiss-kissr-gnrh mRNAs in different brain regions of sexually differentiated males and females indicated differences in their regional distribution. These results suggest possible involvement of Kiss-KissR-GnRH systems during early development and gonadal sex differentiation in the chub mackerel.
