Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation

Sethu Selvaraj, Hajime Kitano, Masafumi Amano, Hirofumi Ohga, Michio Yoneda, Akihiko Yamaguchi, Akio Shimizu, Michiya Matsuyama

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Background: Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation.Methods: Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay.Results: Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms.Conclusion: The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel.

Original languageEnglish
Article number64
JournalReproductive Biology and Endocrinology
Volume10
DOIs
Publication statusPublished - Aug 27 2012

Fingerprint

Kisspeptins
Ovulation
Gonadotropin-Releasing Hormone
Fishes
Brain
Messenger RNA
Oocytes
Peptides
Perciformes
Cyprinidae
Fluoroimmunoassay
Pituitary Gonadotropins
Pituitary Hormones
Real-Time Polymerase Chain Reaction

All Science Journal Classification (ASJC) codes

  • Developmental Biology
  • Endocrinology
  • Reproductive Medicine

Cite this

Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation. / Selvaraj, Sethu; Kitano, Hajime; Amano, Masafumi; Ohga, Hirofumi; Yoneda, Michio; Yamaguchi, Akihiko; Shimizu, Akio; Matsuyama, Michiya.

In: Reproductive Biology and Endocrinology, Vol. 10, 64, 27.08.2012.

Research output: Contribution to journalArticle

@article{6f105868771543b8b2a3b41fa8644108,
title = "Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation",
abstract = "Background: Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation.Methods: Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay.Results: Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms.Conclusion: The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel.",
author = "Sethu Selvaraj and Hajime Kitano and Masafumi Amano and Hirofumi Ohga and Michio Yoneda and Akihiko Yamaguchi and Akio Shimizu and Michiya Matsuyama",
year = "2012",
month = "8",
day = "27",
doi = "10.1186/1477-7827-10-64",
language = "English",
volume = "10",
journal = "Reproductive Biology and Endocrinology",
issn = "1477-7827",
publisher = "BioMed Central",

}

TY - JOUR

T1 - Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation

AU - Selvaraj, Sethu

AU - Kitano, Hajime

AU - Amano, Masafumi

AU - Ohga, Hirofumi

AU - Yoneda, Michio

AU - Yamaguchi, Akihiko

AU - Shimizu, Akio

AU - Matsuyama, Michiya

PY - 2012/8/27

Y1 - 2012/8/27

N2 - Background: Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation.Methods: Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay.Results: Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms.Conclusion: The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel.

AB - Background: Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation.Methods: Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay.Results: Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms.Conclusion: The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel.

UR - http://www.scopus.com/inward/record.url?scp=84865322751&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84865322751&partnerID=8YFLogxK

U2 - 10.1186/1477-7827-10-64

DO - 10.1186/1477-7827-10-64

M3 - Article

VL - 10

JO - Reproductive Biology and Endocrinology

JF - Reproductive Biology and Endocrinology

SN - 1477-7827

M1 - 64

ER -