The Journal of Clinical Endocrinology & Metabolism · 2000 · 256 citations · 0 references
Life SciencesEndocrinologyPhysiologyHormone BiochemistryNeuroendocrinologyReproductive EndocrinologyGrowth HormoneHormone ReleaseHormone SecretionHypothalamic-pituitary RegulationPituitary Gland FunctionPituitary HormonesGhrelin BiologyGhrelin SignalingHormone Release KineticsPulsatile Growth Hormone Release
Ghrelin, an endogenous ligand for the GH secretagogue receptor, is part of a novel system regulating GH release, yet its GH‑releasing activity and other endocrine effects in humans remain poorly understood. The study aimed to evaluate the endocrine responses to synthetic human ghrelin, focusing on GH, ACTH, cortisol, PRL, LH, FSH, and TSH. Four healthy men received intravenous ghrelin at 0.2, 1.0, and 5.0 µg/kg, producing dose‑dependent GH peaks of 43.3, 81.5, and 107.0 ng/mL at 30 minutes. Ghrelin induced dose‑dependent GH release and modest increases in ACTH, cortisol, and PRL, with the lowest dose producing minimal hormone peaks, while LH, FSH, and TSH remained unchanged, demonstrating that ghrelin strongly stimulates GH release in humans.
Ghrelin is a recently identified endogenous ligand for the GH secretagogue receptor and is involved in a novel system for regulating GH release. However, little is known about its GH-releasing activity and other endocrine effects in humans. To address this issue, we studied the GH, ACTH, cortisol, PRL, LH, FSH, and TSH responses to synthetic human ghrelin. In four normal male adults (28–37 yr), iv ghrelin administration released GH in a dose-dependent manner and 0.2, 1.0, and 5.0 μg/kg ghrelin produced 43.3 ± 6.0, 81.5 ± 12.7, and 107.0 ± 10.7 ng/mL of the GH peak values at 30 min, respectively. ACTH, cortisol, and PRL levels were also elevated after ghrelin injection, while the lowest dose (0.2 μg/kg) resulted in only minimum peak values of these hormones (22.8 ± 3.0 pg/mL, 9.4 ± 1.9 μg/dL, and 4.6 ± 0.6 ng/mL, respectively). There were no significant changes in LH, FSH, or TSH levels. This is the first study showing evidence that ghrelin strongly stimulates GH release in humans.