gonadotropin-inhibitory hormoneplay important roles in mammalian reproductive system. Kisspeptin stimulates the GtH release and synthesis via control of GnRH secretion. In contrastGnIH inhibits the GtH release and synthesis directly or via control of GnRH secretion. Howevermuch less is known about these two novel neuropeptide in teleost fish. We have isoiated kisspeptidekiss2 cDNAs from goldfish and zebrafish by a combination of bioinformatics method and PCR cloning. Genomic syteny analysis revealed that kisspeptin and GnIH were preserved in vertebrates during evolutionand indicated that the two Kisspeptin isoforms were created by ancient duplication events. Sequence analysis showed that the functional regions of kisspeptin were relatively conserved in vertebrateswhile that of GnIH varied greatly.RT-PCR analysis demonstrated that the expression of the kiss1sGnIH and GnIHRs were observed in the neuronal and reproductive related tissuespituitaryand gonads. Subsequent studies revealed that both mature goldfish kisspeptin-10 peptides are biologically active as they could functionally interact with the two goldfish receptors expressed in cultured eukaryotic cells to trigger the down-stream signaling pathways with different potencies. The actions of gfKiss1-10（ secretion were further investigated in vitro and in vivo. Intraperitoneal administration of gfKiss1-10 to sexually mature female goldfish could increase the serum LH levels，this peptide does not significantly influence LH release from goldfish pituitary cells in primary cultureindicating that the peptide does not exert its actions at the pituitary level. Whereas gfKiss2-10 appears to be a much less potent peptide as it exhibits no significant in vivo bioactivity and is also inactive on the primary pituitary cells.On the other handIntraperitoneal administration of the mature zebrafish GnIH peptide couldsignificantly reduce the basal serum LH level in goldfish. These data indicated that kisspeptin/GPR54 and GnIH/GnIHRs systems were also operative in teleost fish.