Ghrelin: a metabolic signal affecting the reproductive system

The effects of streptozotocin-induced diabetes on ghrelin expression in rat testis: biochemical and immunohistochemical study

“…Circulating ghrelin has been found to affect gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH) and luteinizing hormone (LH) serum levels and as a result to act on rat hypothalamic--pituitary gonadal axis (HPGA) [10][11]. Also, it has been shown that ghrelin and its functional receptor are expressed in reproductive organs such as ovary, uterus, prostate, and testes [11][12][13].…”

The effect of intracerebroventricular infusions of ghrelin on the secretory activity of the GnRH/LH system in peripubertal ewes

“…Apart from its GH-releasing effect, several other physiological actions of ghrelin have been reported. Ghrelin stimulates food intake, regulates glucose metabolism, secretion and motility of the gastrointestinal tract, and affects pancreatic and cardiovascular functions (Lorenzi et al, 2009). Although the main source of ghrelin is the oxyntic cells in the gastric mucosa, the proximal intestine, pancreas, pituitary and hypothalamus also produce ghrelin (reviewed in Muccoli et al, 2011).…”

“…It has been suggested that ghrelin is involved in the regulation of reproductive function (reviewed in Lorenzi et al, 2009) based on the systemic effects it exerts at both at the hypothalamus and pituitary (Fernández-Fernández et al, 2004;Angelidis et al, 2013) and gonadal levels (Miller et al, 2005;Harrison et al, 2008). Moreover, ghrelin and its receptor, GHSR-1a, are expressed throughout the HPG axis of humans, rodents (Lorenzi et al, 2009), and sheep (Miller et al, 2005).…”

“…Nevertheless, the mechanisms that link reproductive processes and body energy reserves have not been fully explored; it is known, however, that endocrine signals governing energy homeostasis, such as NPY, leptin and orexins, are also involved in the control of reproductive function by acting at different levels of the HPG axis (Wańkowska et al, 2002;Barreiro et al, 2004;Wójcik-Gładysz et al, 2009). It has been suggested that ghrelin is involved in the regulation of reproductive function (reviewed in Lorenzi et al, 2009) based on the systemic effects it exerts at both at the hypothalamus and pituitary (Fernández-Fernández et al, 2004;Angelidis et al, 2013) and gonadal levels (Miller et al, 2005;Harrison et al, 2008). Moreover, ghrelin and its receptor, GHSR-1a, are expressed throughout the HPG axis of humans, rodents (Lorenzi et al, 2009), and sheep (Miller et al, 2005).…”

Histomorphometric features of ventral prostate in different aged rats after central ghrelin treatment

“…In the last years an "unexpected" reproductive facet of ghrelin emerged and indicated that circulating ghrelin might contribute to the functional control of the reproductive axis and its integration with energy balance Lorenzi et al 2009). Significant amount of data gathered so far indicate that ghrelin participates in the regulation of reproductive physiology by two distinct, probably overlapping pathways: (i) through systemic release of the stomach-derived peptide, which acts at all levels of hypothalamic-pituitary-gonadal (HPG) axis, and (ii) through biological actions of locally expressed ghrelin on reproductive organs (Tanaka et al 2001;Lorenzi et al 2009). …”