Abnormal circulating hormone concentration Elevated circulating ghrelin concentration 2024-03-02T10:34:04Z Ghrelin exercises a wide range of functions including, regulation of food intake and energy metabolism, stimulation of gastric acid secretion, motility and pancreatic protein output, modulation of cardiovascular function, stimulation of osteoblast proliferation and bone formation, stimulation of neurogenesis and myogenesis, learning and memory, thymopoiesis, sleep/wake rhythm, aging and a neuroprotective role in neurodegenerative diseases (e.g., Parkinson's disease). The concentration of ghrelin in the blood circulation is above the upper limit of normal. Ghrelin is a 28-amino-acid peptide predominantly secreted in the stomach and stimulates appetite and growth hormone (GH) release.