Adrenocorticotropin/Cortisol and Arginine-Vasopressin Secretory Patterns in Response to Ghrelin in Normal Men

Abstract

This study was performed in order to establish the secretory patterns and the possible relationships between the adrenocorticotropin (ACTH)/cortisol and arginine vasopressin (AVP) responses in normal men to the systemic administration of ghrelin, an endogenous ligand for the growth hormone secretagogue receptor. For this purpose, a bolus of 1 µg/kg ghrelin was injected intravenously in 9 normal men. AVP, ACTH and cortisol significantly rose in response to ghrelin injection; however, in all subjects the AVP rise preceded the ACTH/cortisol responses. In fact, the mean peak levels of AVP, ACTH and cortisol after ghrelin injection were observed at 15, 30 and 45 min, respectively. When peak AVP responses to ghrelin were considered together with ACTH and cortisol peak levels, highly significant positive correlations were observed (AVP and ACTH, r = 0.94, p < 0.001; AVP and cortisol, r = 0.92, p < 0.001). In conclusion, this study shows that the AVP response to ghrelin precedes the concomitant ACTH/cortisol rise and that these hormonal responses are highly positively correlated. These observations support the hypothesis that AVP mediates ghrelin-induced ACTH secretion in normal men.

Ghrelin gene products, receptors, and GOAT enzyme: biological and pathophysiological insight

“…Thus, native AG stimulates AVP release from rat posterior pituitary gland, probably via an indirect action mediated by NPY neurons (Ishizaki et al 2002, Wren et al 2002. Notably, AG-induced ACTH release has also been suggested to be mediated by the AG action on AVP secretion, because the AG-induced AVP rise precedes the increase in ACTH and cortisol levels in response to AG injection in healthy men (Coiro et al 2005). On the other hand, the relationship between the OT and ghrelin systems has not been fully elucidated.…”

Concordant and discordant adrenocorticotropin (ACTH) responses induced by growth hormone-releasing peptide-2 (GHRP-2), corticotropin-releasing hormone (CRH) and insulin-induced hypoglycemia in patients with hypothalamopituitary disorders: evidence for direct ACTH releasing activity of GHRP-2

“…The mechanism underlying GHRP-2's stimulation of ACTH release remains controversial. Previous studies in humans suggested that GHRP's ACTH-releasing activity may be mediated via CRH and/or AVP [3,5,7,11], or independent on both peptides [12]. Very recently, Kamoi et al [13] showed that GHRP-2 does not stimulate AVP secretion.…”

GH-releasing Peptide-2 does not Stimulate Arginine Vasopressin Secretion in Healthy Men

“…Since GhRp-2 has a role as a ghrelin receptor agonist, the GhRp-2 test could provide a non-osmotic stimulus for AVp secretion. coiro et al demonstrated that ghrelin stimulated AVp secretion in healthy men with fasting [10]. there were no significant differences in sex, age, and bMi between the two studies.…”

“…ten healthy men, aged 24 to 34 years (mean age, 30 ± 0.9 years), with bMis ranging from 20.0 to 26.7 (mean, 22.0 ± 0.7) kg/m 2 , were studied based on the method of coiro et al [10]. they had received no drugs.…”

“…secreted from the stomach and circulates in the bloodstream under fasting conditions [5], and the GhSs have a stimulating effect not only on Acth via cRh in animals [6,7] and humans [4,[8][9][10], but also on arginine vasopressin (AVp) in animals [6,11,12] and humans [9,10]. interestingly, ghrelin plays a stimulatory role in AVp release mediated by neuropeptide y (npy) neurons in rat [11,12].…”