Gonadotropin-inhibitory hormone (GnIH) in the amphibian brain and its relationship with the gonadotropin releasing hormone (GnRH) system: An overview.
It is well known that the hypothalamic neuropeptide gonadotropin-releasing hormone (GnRH) plays an important role as a primary factor regulating gonadotropin secretion in reproductive processes in vertebrates. The discovery of the presence of a gonadotropin-inhibitory hormone (GnIH) in the brains of birds has further contributed to our understanding of the reproduction control by the brain. GnIH plays a key role in inhibition of reproduction and acts on the pituitary gland and GnRH neurons via a novel G protein-coupled receptor (GPR147). GnIH decreases gonadotropin synthesis and release, thus inhibiting gonadal development and maintenance. The GnRH and GnIH neuronal peptidergic systems are well reported in mammals and birds, but limited information is available regarding their presence and localization in the brains of other vertebrate species, such as reptiles, amphibians and fishes. The aim of this review is to compile and update information on the localization of GnRH and GnIH neuronal systems, with a particular focus on amphibians, summarizing the neuroanatomical distribution of GnIH and GnRH and emphasizing the discovery of GnIH based on RFamide peptides and GnIH orthologous peptides found in other vertebrates and their functional significance.
Department of Zoology, RTM Nagpur University Campus, Nagpur 440 033, MS, India. Electronic address: agj213@hotmail.com.
Arun G
AG
Jadhao
Department of Environmental, Biological, and Pharmaceutical Sciences & Technologies, Second University of Naples, 81100 Caserta, Italy.
Claudia
C
Pinelli
Department of Biology, University of Naples "Federico II", 80126 Napoli, Italy.
Biagio
B
D'Aniello
Laboratory of Integrative Brain Sciences, Department of Biology and Centre for Medical Life Science, Waseda University, Tokyo 162-8480, Japan.
Kazuyoshi
K
Tsutsui
D000663:Amphibians / Q000254:growth & development*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D006062:Gonadotropins / Q000037:antagonists & inhibitors*; D009479:Neuropeptides / Q000378:metabolism
D006062:Gonadotropins; D009479:Neuropeptides; D007987:Gonadotropin-Releasing Hormone
Gonadotropin-inhibitory hormone (GnIH); Gonadotropin-releasing hormone (GnRH); Neuropeptides; Pituitary; RFamide peptides; Reproduction