Expression changes of mRNAs encoding kisspeptins and their receptors and gonadotropin-releasing hormones during early development and gonadal sex differentiation periods in the brain of chub mackerel (Scomber japonicus).
Selvaraj. Sethu S; Kitano. Hajime H; Ohga. Hirofumi H; Yamaguchi. Akihiko A; Matsuyama. Michiya M
Key Findings
- Kisspeptin and its receptors are expressed at higher levels in the first two weeks after hatching.
- In both male and female fish, kiss2 and its two receptors peak at 37 days post‑hatch, while kiss1 does not change much.
- All three GnRH hormone mRNAs are highest at 45 days post‑hatch and then drop by day 60.
- The distribution of these genes varies across different brain regions in sexually differentiated fish.
Practical Outcomes
- The findings are specific to fish development and do not provide actionable guidance for human health, longevity, or performance optimization. Biohackers looking for protocols or dosing information on kisspeptin‑10 will not gain practical benefits from this study.
Summary
The study looked at how certain brain chemicals (kisspeptins and related hormones) change as young chub mackerel grow and develop male or female organs. It found that these chemicals are most active early in life and show different patterns in males and females during the sex‑differentiation stage.
Abstract
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 (0-30dphs) and gonadal sex differentiation periods (37-60dphs). Absolute expression level of kiss-kissr-gnrh in the whole head was higher between 0 and 15dphs, 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 60dphs. In both males and females, kiss2, kissr1, and kissr2 levels were higher at 37dph, in comparison to 45 and 60dphs, with kiss1 showing no significant differences. Levels of all three gnrh mRNAs were higher at 45dph, in comparison to 60dph. 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.
Study Information
pubmed
2014
2014-10-07T00:00:00.000Z
10.1016/j.ygcen.2014.09.019
23
134