Rapid inhibition of female sexual behavior by gonadotropin-inhibitory hormone (GnIH)

Abstract

TitleRapid inhibition of female sexual behavior by gonadotropin-inhibitory hormone (GnIH). Abstract Gonadotropin-releasing hormone (GnRH) is largely responsible for the initiation of sexual behaviors; one form of GnRH activates a physiological cascade causing gonadal growth and gonadal steroid feedback to the brain, and another form is thought to act as a neurotransmitter to enhance sexual receptivity. In contrast to GnRH, gonadotropin-inhibitory hormone (GnIH) inhibits gonadotropin release. The distribution of GnIH in the avian brain suggests that it has not only hypophysiotropic actions but also unknown behavioral actions. GnIH fibers are present in the median eminence (ME) and are in apparent contact with chicken GnRH (cGnRH)-I and -II neurons and fibers. In birds, cGnRH-I regulates pituitary gonadotropin release, whereas cGnRH-II enhances copulation solicitation in estradiol-primed females exposed to male song. In the present study, we determined the effects of GnIH administered centrally to female white-crowned sparrows. A physiological dose of GnIH reduced circulating LH and inhibited copulation solicitation, without affecting locomotor activity. Using rhodaminated GnIH, putative GnIH binding sites were seen in the ME close to GnRH-I fiber terminals and in the midbrain on or close to GnRH-II neurons. These data demonstrate direct effects of GnIH upon reproductive physiology and behavior, possibly via separate actions on two forms of GnRH.

Rat RFamide-related peptide-3 stimulates GH secretion, inhibits LH secretion, and has variable effects on sex behavior in the adult male rat

“…These data suggest that RFRP-3 may be an important central player in maintaining homeostasis within the reproductive system. Recent reports have suggested that rat RFRP-3 is functionally similar to the described GnIH in birds (Bentley, Jensen, Kaur, Wacker, Tsutsui, and Wingfield, 2006;Kriegsfeld et al, 2006). Although structurally related to GnIH, the mammalian homolog, RFRP-3, appears to have multiple physiologic and behavioral functions in the adult male rat.…”

Gene expression profiles in the pituitary glands of Sichuan White geese during prelaying and laying periods

“…The GnRH system plays a key role in vertebrate reproduction, and GnIH decreases gonadotropin release and synthesis via the GnRH system in birds (Tsutsui et al, 2000;Ciccone et al, 2004;Osugi et al, 2004;Bentley et al, 2006;Ubuka et al, 2006). GnRH and GnIH are secreted by the hypothalamus and partially regulate the gonadotropins FSH and LH, as well as PRL (Tsutsui et al, 2012).…”

“…Another key neurohormone in the HPG axis is gonadotropin-inhibitory hormone (GnIH), which is a neuropeptide expressed in quail (Tsutsui et al, 2000), chicken (Ikemoto and Park, 2005), sparrow (Osugi et al, 2004), starling (Ubuka et al, 2008), zebra finch (Tobari et al, 2010), and goose. GnIH decreases gonadotropin release and synthesis via the GnRH system in birds (Tsutsui et al, 2000;Ciccone et al, 2004;Osugi et al, 2004;Bentley et al, 2006;Ubuka et al, 2006).…”

Role of LPXRFamide peptide in the neuroendocrine regulation of reproduction in fish

“…The synchronous and diurnal variations of LPXRFa and its receptor genes indicate that the action of LPXRFa on the diencephalon is highly dependent on time, and thereby LPXRFa might be involved in the control of the cyclic reproductive activity of grass puffer. One of possible target sites of LPXRFa action in the diencephalon may be GnRH neurons as reported in other vertebrates [34,37,45]. RFRP-3 Rat Inhibition of GnRH-elicited GTH release [62] RFRP-3 Ovin Inhibition of GnRH-elicited GTH release [58] Bullfrog fGRP Bullfrog Stimulation of GH release [17] fGRP-RP-2 Bullfrog Stimulation of GH/PRL release [19] Goldfish LPXRFa-1 Sockeye salmon Stimulation of GTH and GH release [54] Goldfish LPXRFa-2 Sockeye salmon Stimulation of GTH and GH release [54] Goldfish LPXRFa-3 Sockeye salmon Stimulation of GTH and GH release [54] Zebrafish LPXRFa-3 Goldfish Inhibition of LH release [43] Goldfish LPXRFa-1 Grass puffer Stimulation of GTH release [51] Photoperiodic regulation of LPXRFa gene has been reported in some vertebrates.…”

“…QRFP and 26RFa [27,28]. Among these groups of the RFamide peptide family, the LPXRFa group regulates the release of various pituitary hormones; however, the precise effects of LPXRFa vary distinctly among animal classes [9,10,12,13,19,[29][30][31][32][33][34][35][36][37][38][39].…”