1. GIP Receptor Antagonism Eliminates Paradoxical Growth Hormone Secretion in Some Patients With Acromegaly.
- Author
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Jensen MH, Gasbjerg LS, Skov-Jeppesen K, Jacobsen JCB, Poulsen SS, Zhou C, Jakubauskaite R, Poulsen FR, Bonde C, Albarazi M, Halle B, Christiansen CB, Sanni SJ, Byberg S, Hoe B, Holst JJ, Dela F, Rasmussen AK, Knop FK, Arlien-Søborg MC, Melmed S, Jørgensen JOL, Andersen MS, Hartmann B, Klose MC, Feldt-Rasmussen U, Sparre-Ulrich AH, and Rosenkilde MM
- Subjects
- Humans, Male, Female, Middle Aged, Adult, Adenoma metabolism, Adenoma drug therapy, Adenoma pathology, Peptide Fragments metabolism, Aged, Acromegaly drug therapy, Acromegaly metabolism, Receptors, Gastrointestinal Hormone metabolism, Receptors, Gastrointestinal Hormone antagonists & inhibitors, Gastric Inhibitory Polypeptide metabolism, Human Growth Hormone metabolism, Glucose Tolerance Test, Growth Hormone-Secreting Pituitary Adenoma metabolism, Growth Hormone-Secreting Pituitary Adenoma drug therapy, Growth Hormone-Secreting Pituitary Adenoma pathology
- Abstract
Context: About 30% of patients with active acromegaly experience paradoxically increased growth hormone (GH) secretion during the diagnostic oral glucose tolerance test (OGTT). Endogenous glucose-dependent insulinotropic polypeptide (GIP) is implicated in this paradoxical secretion., Objective: We used the GIP receptor (GIPR) antagonist GIP(3-30)NH2 to test the hypothesis that GIP mediates this paradoxical response when GIPR is abundantly expressed in somatotropinomas., Methods: A total of 25 treatment-naive patients with acromegaly were enrolled. Each patient underwent one OGTT during simultaneous placebo infusion and one OGTT during a GIP(3-30)NH2 infusion. Blood samples were drawn at baseline and regularly after infusions to measure GH. We assessed pituitary adenoma size by magnetic resonance imaging and GIPR expression by immunohistochemistry on resected somatotropinomas. For mechanistic confirmation, we applied in vitro and ex vivo approaches. The main outcome measure was the effect of GIP(3-30)NH2 on paradoxical GH secretion during OGTT as a measure of GIP involvement., Results: In 4 of 7 patients with paradoxical GH secretion, GIP(3-30)NH2 infusion completely abolished the paradoxical response (P = .0003). Somatotrophs were available from 3 of 4 of these patients, all showing abundant GIPR expression. Adenoma size did not differ between patients with and without paradoxical GH secretion., Conclusion: Of 25 patients with acromegaly, 7 had paradoxical GH secretion during OGTT, and pharmaceutical GIPR blockade abolished this secretion in 4. Corresponding somatotroph adenomas abundantly expressed GIPR, suggesting a therapeutic target in this subpopulation of patients. In vitro and ex vivo analyses confirmed the role of GIP and the effects of the antagonist., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.)
- Published
- 2025
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