Role of ghrelin in reproduction

Abstract

Ghrelin, the endogenous ligand of GH secretagogue receptor type 1a, has emerged as a pleiotropic modulator of diverse biological functions, including energy homeostasis and, lately reproduction. Here, we review recent reports evaluating the reproductive effects and sites of action of ghrelin, with particular emphasis regarding its role as a molecule integrating reproductive function and energy status. Data gleaned from rodent studies clearly show that besides having direct gonadal effects, ghrelin may participate in the regulation of gonadotropin secretion and it may influence the timing of puberty. In addition, experimental data showing that ghrelin and/or its receptor are expressed in normal human ovary and testis as well as in human ovarian and testicular tumors raise the possibility that the ghrelin system may be involved in the control of cell proliferation in these tumors. We propose that ghrelin either acting as an endocrine and/or paracrine signal may play a major role in the endocrine network that integrates energy balance and reproduction.

Involvement of the transcription factor STAT1 in the regulation of porcine ovarian granulosa cell functions treated and not treated with ghrelin

“…These data are in line with related data concerning the proliferation-stimulating effect of ghrelin on testicular tumours (Garcia et al 2007), some nonreproductive (prostatic cancer) cells (Yeh et al 2005), avian (Sirotkin & Grossmann 2006) and porcine (Rak & Gregoraszczuk 2008) ovarian cells, but not with a report on the inhibitory action of ghrelin on proliferation of cultured Leydig cells (Tena-Sempere 2005). Figure 3 Influence of ghrelin on expression of caspase-3 in cultured porcine granulosa cells subjected (Overexpression of STAT1) and not subjected (Control) to transfection with gene construct encoding STAT1.…”

“…The inhibitory effect of ghrelin on onset of rat puberty previously reported (Tena-Sempere 2008) indicates that the net effect on the hypothalamo-hypophysial-gonadal system and the biological role of this hormone can change during sexual maturation. Furthermore, the inhibitory influence of calorific intake on ghrelin production and the influence of ghrelin on reproductive functions confirm the hypothesis (Barreiro & Tena-Sempere 2004, Tena-Sempere 2005, 2008, Garcia et al 2007) that ghrelin can be a mediator of the effects of nutrition on reproductive processes.…”

L’ampk : un lien entre métabolisme et reproduction ?

“…Elle inhibe la sécrétion de LH/FSH en réponse au GnRH [23] et est exprimée dans l'ovaire (expression cyclique). Son expression très prononcée dans le corps jaune est fonction de la progestérone [23].…”

“…Son expression très prononcée dans le corps jaune est fonction de la progestérone [23]. Ainsi, l'AMPK pourrait être l'un des senseurs énergéti-ques à l'interface métabolisme/reproduction, pouvant expliquer les effets doubles (métaboliques et reproductifs) de certaines hormones telles la ghréline et les adipokines.…”

Effects of peripheral ghrelin on growth performance, selected blood biochemical parameters and thyroid hormone in Japanese quail (Coturnix coturnix japonica)

“…These reports have shown its various regulatory functions namely; growth hormone -releasing activity (7), appetite regulation, weight control and energy metabolism (15,23,24) and reproductive effects (5), whereas, the regulatory roles of ghrelin peptide are not limited to the effects mentioned. Ghrelin was identified in birds by Kaiya et al (8); in chicken (Gallus gallus domesticus) where it formed with 26-amino-acids.…”