Obestatin partially suppresses ghrelin stimulation of appetite in "high-responders" grass carp, Ctenopharyngodon idellus.
Ghrelin and obestatin are two gastrointestinal peptides obtained by post-translational processing of a common precursor, preproghrelin. The effect of obestatin on food intake is still controversial. The aim of the present study was to investigate the effects of ghrelin and obestatin on food intake in grass carp, Ctenopharyngodon idellus. Fish received intraperitoneal (IP) injection of saline, ghrelin (100 ng g(-1)BW), obestatin-like (25 ng g(-1)BW) and ghrelin in combination with obestatin-like. Ghrelin stimulation of food intake varied considerably among individual fish with 70.8% eliciting a robust response. In these high-responders, food intake was significantly increased by IP ghrelin within 2 h. Co-administration of ghrelin and obestatin-like resulted in a decrease in food intake, indicating that obestatin was able to antagonize the effect of ghrelin. However, IP obestatin-like alone could not regulate food intake in grass carp. RT-PCR analysis demonstrated that IP ghrelin peptide led to a significant increase in mRNA abundance of NPY, Y8a and Y8b genes compared to saline injected fish, while in combination with obestatin-like peptide decreased ghrelin-induced gene expressions of these three genes. IP sole obestatin-like peptide did not modify the expression levels of NPY, Y8a, Y8b, CART and POMC compared to the control group. Therefore, IP administration of obestatin-like peptide, partially blocking the ghrelin-induced appetite, investigated the possible involvement of obestatin as a mediator of the ghrelin stimulatory action on food intake, at least in "high-responders" grass carp.
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China.
Xiaochen
X
Yuan
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China.
Wenjing
W
Cai
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China. Electronic address: xufang_liang@hotmail.com.
Xu-Fang
XF
Liang
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China.
Hang
H
Su
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China. Electronic address: yyc@mail.hzau.edu.cnAixuan.
Yongchao
Y
Yuan
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China.
Aixuan
A
Li
College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei 430070, China.
Ya-Xiong
YX
Tao
D000818:Animals; D001066:Appetite; D002347:Carps / Q000502:physiology*; D054439:Ghrelin / Q000008:administration & dosage*
D054439:Ghrelin
CART; CCK; Food intake; Interactions; NPY; mRNA expression