Limits...
Gonadotropin-releasing hormone 2 suppresses food intake in the zebrafish, Danio rerio.

Nishiguchi R, Azuma M, Yokobori E, Uchiyama M, Matsuda K - Front Endocrinol (Lausanne) (2012)

Bottom Line: ICV injection of GnRH2 at 0.1 and 1 pmol/g body weight (BW) induced a marked decrease of food consumption in a dose-dependent manner during 30 min after feeding.Levels of GnRH2 mRNA obtained from fish that had been provided excess food for 7 days were higher than those in fish that had been fed normally.These results suggest that, in zebrafish, GnRH2 acts as an anorexigenic factor, as is the case in goldfish.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama Toyama, Japan.

ABSTRACT
Gonadotropin-releasing hormone (GnRH) is an evolutionarily conserved neuropeptide with 10 amino acid residues, of which several structural variants exist. A molecular form known as GnRH2 ([His(5) Trp(7) Tyr(8)]GnRH, also known as chicken GnRH II) is widely distributed in vertebrates except for rodents, and has recently been implicated in the regulation of feeding behavior in goldfish. However, the influence of GnRH2 on feeding behavior in other fish has not yet been studied. In the present study, therefore, we investigated the role of GnRH2 in the regulation of feeding behavior in a zebrafish model, and examined its involvement in food intake after intracerebroventricular (ICV) administration. ICV injection of GnRH2 at 0.1 and 1 pmol/g body weight (BW) induced a marked decrease of food consumption in a dose-dependent manner during 30 min after feeding. Cumulative food intake was significantly decreased by ICV injection of GnRH2 at 1 pmol/g BW during the 30-min post-treatment observation period. The anorexigenic action of GnRH2 was completely blocked by treatment with the GnRH type I receptor antagonist Antide at 25 pmol/g BW. We also examined the effect of feeding condition on the expression level of the GnRH2 transcript in the hypothalamus. Levels of GnRH2 mRNA obtained from fish that had been provided excess food for 7 days were higher than those in fish that had been fed normally. These results suggest that, in zebrafish, GnRH2 acts as an anorexigenic factor, as is the case in goldfish.

No MeSH data available.


Related in: MedlinePlus

Effect of ICV administration of Antide on the anorexigenic action of GnRH2. The results are expressed as a percentage of the control, i.e., vehicle-injected, fish. Each column and bar represents the mean and SEM, respectively, and the numbers in parentheses in the panels indicate the number of fish in each group. Significance of differences among experimental groups was evaluated by two-way ANOVA with the Bonferroni’s method in comparison with the vehicle-injected group (**P < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3473230&req=5

Figure 2: Effect of ICV administration of Antide on the anorexigenic action of GnRH2. The results are expressed as a percentage of the control, i.e., vehicle-injected, fish. Each column and bar represents the mean and SEM, respectively, and the numbers in parentheses in the panels indicate the number of fish in each group. Significance of differences among experimental groups was evaluated by two-way ANOVA with the Bonferroni’s method in comparison with the vehicle-injected group (**P < 0.01).

Mentions: Intracerebroventricular administration of GnRH2 alone at 1 pmol/g BW suppressed food intake over a 30-min feeding period, and ICV-injected Antide alone at 25 pmol/g BW did not affect food intake. On the other hand, the same dose of Antide completely abolished the anorexigenic action of ICV-injected GnRH2 at a dose of 1 pmol/g BW, and the efficacy of the antagonist was shown to be significant by two-way ANOVA with Bonferroni’s method (df, F, and P values, 1, 4.39, and 0.04, respectively; Figure 2).


Gonadotropin-releasing hormone 2 suppresses food intake in the zebrafish, Danio rerio.

Nishiguchi R, Azuma M, Yokobori E, Uchiyama M, Matsuda K - Front Endocrinol (Lausanne) (2012)

Effect of ICV administration of Antide on the anorexigenic action of GnRH2. The results are expressed as a percentage of the control, i.e., vehicle-injected, fish. Each column and bar represents the mean and SEM, respectively, and the numbers in parentheses in the panels indicate the number of fish in each group. Significance of differences among experimental groups was evaluated by two-way ANOVA with the Bonferroni’s method in comparison with the vehicle-injected group (**P < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3473230&req=5

Figure 2: Effect of ICV administration of Antide on the anorexigenic action of GnRH2. The results are expressed as a percentage of the control, i.e., vehicle-injected, fish. Each column and bar represents the mean and SEM, respectively, and the numbers in parentheses in the panels indicate the number of fish in each group. Significance of differences among experimental groups was evaluated by two-way ANOVA with the Bonferroni’s method in comparison with the vehicle-injected group (**P < 0.01).
Mentions: Intracerebroventricular administration of GnRH2 alone at 1 pmol/g BW suppressed food intake over a 30-min feeding period, and ICV-injected Antide alone at 25 pmol/g BW did not affect food intake. On the other hand, the same dose of Antide completely abolished the anorexigenic action of ICV-injected GnRH2 at a dose of 1 pmol/g BW, and the efficacy of the antagonist was shown to be significant by two-way ANOVA with Bonferroni’s method (df, F, and P values, 1, 4.39, and 0.04, respectively; Figure 2).

Bottom Line: ICV injection of GnRH2 at 0.1 and 1 pmol/g body weight (BW) induced a marked decrease of food consumption in a dose-dependent manner during 30 min after feeding.Levels of GnRH2 mRNA obtained from fish that had been provided excess food for 7 days were higher than those in fish that had been fed normally.These results suggest that, in zebrafish, GnRH2 acts as an anorexigenic factor, as is the case in goldfish.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama Toyama, Japan.

ABSTRACT
Gonadotropin-releasing hormone (GnRH) is an evolutionarily conserved neuropeptide with 10 amino acid residues, of which several structural variants exist. A molecular form known as GnRH2 ([His(5) Trp(7) Tyr(8)]GnRH, also known as chicken GnRH II) is widely distributed in vertebrates except for rodents, and has recently been implicated in the regulation of feeding behavior in goldfish. However, the influence of GnRH2 on feeding behavior in other fish has not yet been studied. In the present study, therefore, we investigated the role of GnRH2 in the regulation of feeding behavior in a zebrafish model, and examined its involvement in food intake after intracerebroventricular (ICV) administration. ICV injection of GnRH2 at 0.1 and 1 pmol/g body weight (BW) induced a marked decrease of food consumption in a dose-dependent manner during 30 min after feeding. Cumulative food intake was significantly decreased by ICV injection of GnRH2 at 1 pmol/g BW during the 30-min post-treatment observation period. The anorexigenic action of GnRH2 was completely blocked by treatment with the GnRH type I receptor antagonist Antide at 25 pmol/g BW. We also examined the effect of feeding condition on the expression level of the GnRH2 transcript in the hypothalamus. Levels of GnRH2 mRNA obtained from fish that had been provided excess food for 7 days were higher than those in fish that had been fed normally. These results suggest that, in zebrafish, GnRH2 acts as an anorexigenic factor, as is the case in goldfish.

No MeSH data available.


Related in: MedlinePlus