Our understanding of this hypothalamus-pituitary-gonadal axis has quickly expanded during the last decade.
Two novel hypothalamic Arg-Phe-amide- related peptides, kisspeptin and gonadotropin-inhibitory hormone, may be important regulators of the reproductive axis. Kisspeptins are currently recognized as the most potent activators of the hypothalamus-pituitary-gonadal axis. Kisspeptin and its receptor, G protein-coupled receptor 54 (GPR54), are expressed on gonadotropin-releasing hormone neurons, thus regulating the reproductive axis.
Kisspeptins strongly release gonadotropin- releasing hormone and luteinizing hormone, even at pre-puberty. Kisspeptin/GPR54 is important for the regulation of sexual maturation and the development of the reproductive system.
Prof. Haluk Kelestimur and colleagues from Medical School, Firat University, Elazig, Turkey used the GT1-7 cell line-expressing gonadotropin-releasing hormone as a model and found that gonadotropin-inhibitory hormone and Arg-Phe-amide-related peptide-1 may have inhibitory effects on kisspeptin-activated gonadotropin-releasing hormone neurons without affecting [Ca2+]i.
These findings which were in the Neural Regeneration Research
(Vol. 8, No. 18, 2013) that Arg-Phe-amide-related-peptide-1, in addition to Arg-Phe-amide-related-peptide-3, may be involved in the modulation of the hypothalamus- pituitary-gonadal axis.