Human ghrelin decreases pituitary response to GnRH in superovulated ewes

dc.contributor.author	Dovolou, E	en
dc.contributor.author	Chadio, S	en
dc.contributor.author	Messinis, IE	en
dc.contributor.author	Rekkas, CA	en
dc.contributor.author	Deligiannis, C	en
dc.contributor.author	Kalogiannis, D	en
dc.contributor.author	Amiridis, GS	en
dc.date.accessioned	2014-06-06T06:52:37Z
dc.date.available	2014-06-06T06:52:37Z
dc.date.issued	2013	en
dc.identifier.issn	0093691X	en
dc.identifier.uri	http://dx.doi.org/10.1016/j.theriogenology.2013.04.005	en
dc.identifier.uri	http://62.217.125.90/xmlui/handle/123456789/6083
dc.subject	FSH	en
dc.subject	Ghrelin	en
dc.subject	GnRH	en
dc.subject	LH	en
dc.subject	Pituitary	en
dc.subject	Sheep	en
dc.subject.other	estradiol	en
dc.subject.other	follitropin	en
dc.subject.other	ghrelin	en
dc.subject.other	gonadorelin	en
dc.subject.other	insulin	en
dc.subject.other	luteinizing hormone	en
dc.subject.other	progesterone	en
dc.subject.other	somatomedin C	en
dc.subject.other	animal	en
dc.subject.other	article	en
dc.subject.other	blood	en
dc.subject.other	drug effect	en
dc.subject.other	female	en
dc.subject.other	human	en
dc.subject.other	hypophysis	en
dc.subject.other	metabolism	en
dc.subject.other	physiology	en
dc.subject.other	sheep	en
dc.subject.other	superovulation	en
dc.subject.other	FSH	en
dc.subject.other	Ghrelin	en
dc.subject.other	GnRH	en
dc.subject.other	LH	en
dc.subject.other	Pituitary	en
dc.subject.other	Sheep	en
dc.subject.other	Animals	en
dc.subject.other	Estradiol	en
dc.subject.other	Female	en
dc.subject.other	Ghrelin	en
dc.subject.other	Gonadotropin-Releasing Hormone	en
dc.subject.other	Humans	en
dc.subject.other	Insulin	en
dc.subject.other	Insulin-Like Growth Factor I	en
dc.subject.other	Pituitary Gland	en
dc.subject.other	Progesterone	en
dc.subject.other	Sheep	en
dc.subject.other	Superovulation	en
dc.subject.other	Animalia	en
dc.subject.other	Ovis aries	en
dc.title	Human ghrelin decreases pituitary response to GnRH in superovulated ewes	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.theriogenology.2013.04.005	en
heal.publicationDate	2013	en
heal.abstract	In addition to its metabolic role, ghrelin has been found to suppress luteinizing hormone secretion in many species acting mainly at the hypothalamic level. The objectives of the present study were to test the hypothesis that besides its effects on the hypothalamic level, ghrelin exerts a direct action on the pituitary. Twelve cycling ewes were synchronized, using progestagen intravaginal sponges and superovulated using eCG. At the time of sponge withdrawal, animals were allocated into two groups, ghrelin-treated (Gh) and control. Two days after the sponge removal, GnRH was given to synchronize ovulations. Simultaneously with GnRH treatment, animals of the Gh group received the first of four treatments of acylated human ghrelin at a dose of 6 μg/kg body weight iv; three additional treatments of ghrelin iv were given every 15 minutes thereafter. Control animals received saline iv. Blood samples were collected before challenge (-30 and 0 minutes) and at 30, 60, 75, 90, 105, 120, 135, 150, and 180 minutes after GnRH treatment, and were analyzed for LH, FSH, estradiol, progesterone, insulin, and insulin-like growth factor-I concentrations. Ghrelin treatment attenuated GnRH-induced a preovulatory surge of both gonadotrophins, with the effect being greater for LH. No difference was detected for insulin, estradiol, and progesterone concentrations, and insulin-like growth factor-I levels were increased in the Gh group. Our results imply that in sheep, ghrelin conducts specific regulatory effects on the GnRH/LH axis, and provide for the first time strong evidence that besides its central action, ghrelin might regulate gonadotrophin release acting at the pituitary level. © 2013 Elsevier Inc.	en
heal.journalName	Theriogenology	en
dc.identifier.issue	3	en
dc.identifier.volume	80	en
dc.identifier.doi	10.1016/j.theriogenology.2013.04.005	en
dc.identifier.spage	262	en
dc.identifier.epage	268	en