The endocrine response to ghrelin as a function of gender in humans in young and elderly subjects.
Ghrelin modulates somatotroph, lactotroph, corticotroph, and insulin secretion and glucose metabolism. To clarify the influence of gender and age on the endocrine actions of ghrelin in humans, we studied the effects of ghrelin (1.0 micro g/kg iv) or placebo on GH, prolactin (PRL), ACTH, cortisol, insulin, glucagon, and glucose levels in 18 young subjects (YS) and 16 elderly subjects (ES) of both genders. The GH response to GHRH (1.0 micro g/kg iv) was also studied. The GH response to ghrelin in YS was higher (P < 0.01) than in ES and both higher (P < 0.01) than to GHRH, without gender-related differences. In YS ghrelin also induced: 1) gender-independent increase (P < 0.01) in PRL, ACTH, and cortisol levels; 2) gender-independent increase in glucose levels (P < 0.01); 3) decrease (P < 0.01) in insulin levels in male YS; and 4) no change in glucagon. In ES, ghrelin induced gender-independent PRL, ACTH, and cortisol responses (P < 0.01). In ES ghrelin elicited gender-independent transient decrease in insulin (P < 0.01) coupled with increase in glucose levels (P < 0.05). In conclusion, the GH-releasing effect of ghrelin is independent of gender but undergoes age-related decrease. The effect of ghrelin on lactotroph and corticotroph secretion is age and gender independent. In both ES and YS, ghrelin influences insulin secretion and glucose metabolism.
Broglio
Fabio
F
Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, 10126 Turin, Italy.
Benso
Andrea
A
Castiglioni
Carlotta
C
Gottero
Cristina
C
Prodam
Flavia
F
Destefanis
Silvia
S
Gauna
Carlotta
C
van der Lely
Aart Jan
AJ
Deghenghi
Romano
R
Bo
Mario
M
Arvat
Emanuela
E
Ghigo
Ezio
E
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D000375:Aging; D001786:Blood Glucose / Q000032:analysis; D005260:Female; D054439:Ghrelin; D005934:Glucagon / Q000097:blood; D006728:Hormones / Q000097:blood*; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D036361:Peptide Hormones / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D010919:Placebos; D011388:Prolactin / Q000097:blood; D012727:Sex Characteristics
D001786:Blood Glucose; D054439:Ghrelin; D006728:Hormones; D007328:Insulin; D036361:Peptide Hormones; D010919:Placebos; D019382:Human Growth Hormone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D005934:Glucagon; D006854:Hydrocortisone