Ghrelin and GHRP-6-induced ACTH and cortisol release in thyrotoxicosis

• Published in: Pituitary Vol. 12; no. 4; pp. 315 - 321
• Main Authors: Nascif, Sergio Oliva, Molica, Patrícia, Correa-Silva, Silvia Regina, Silva, Marcos Roberto, Lengyel, Ana-Maria Judith
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 2009; Springer US; Springer Nature B.V
• Subjects: Adolescent; Adrenocorticotropic Hormone - metabolism; Adult; Endocrinology; Female; Ghrelin - pharmacology; Human Physiology; Humans; Hydrocortisone - metabolism; Hypothalamo-Hypophyseal System - drug effects; Hypothalamo-Hypophyseal System - metabolism; Male; Medicine; Medicine & Public Health; Oligopeptides - pharmacology; Pituitary-Adrenal System - drug effects; Pituitary-Adrenal System - metabolism; Thyrotoxicosis - metabolism; Young Adult; ACTH; Cortisol; Ghrelin; Thyrotoxicosis
• ISSN: 1386-341X; 1573-7403
• DOI: 10.1007/s11102-009-0181-3

Thyrotoxicosis might alter the hypothalamic-pituitary-adrenal (HPA) axis. We evaluated the effects of ghrelin and GHRP-6 on the HPA axis in 20 hyperthyroid patients and in 9 controls. Mean basal cortisol (μg/dl) and ACTH (pg/ml) levels were higher in hyperthyroidism (cortisol: 10.7 ± 0.7; ACTH: 21.5 ± 2.9) compared to controls (cortisol: 8.1 ± 0.7; ACTH: 13.5 ± 1.8). In thyrotoxicosis ∆ AUC cortisol values (μg/dl.90 min) after ghrelin (484 ± 80) and GHRP-6 (115 ± 63) were similar to controls (ghrelin: 524 ± 107; GHRP-6: 192 ± 73). A significant increase in ∆ AUC ACTH (pg/ml.90 min) after ghrelin was observed in thyrotoxicosis (4,189 ± 1,202) compared to controls (1,499 ± 338). ∆ AUC ACTH values after GHRP-6 were also higher, although not significantly (patients: 927 ± 330; controls: 539 ± 237). In summary, our results suggest that ghrelin-mediated pathways of ACTH release might be activated by thyroid hormone excess, but adrenocortical reserve is maintained.