Introduction Ghrelin is a peptide hormone secreted mainly by the stomach, with minor secretion from other parts of the gastrointestinal tract. It exists in two forms: acylated ghrelin (active form) and des-acylated ghrelin (inactive form). The active form binds to the growth hormone secretagogue receptor (GHSR-1a), initiating biological activity. Growth hormone (GH) is secreted by somatotroph cells in the anterior pituitary gland. Its secretion is mainly stimulated by growth hormone–releasing hormone (GHRH) and inhibited by somatostatin. GH plays essential roles in metabolism, linear growth, and stimulation of insulin-like growth factor-1 (IGF-1) production by the liver and peripheral tissues. Mechanism of Interaction Between Ghrelin and GH 1. Activation of GHSR-1a Receptors Ghrelin binds to the GHSR-1a receptors located in both the hypothalamus and the anterior pituitary. This interaction directly stimulates GH secretion. 2. Interaction with GHRH and Somatostatin Ghrelin acts synergistically with GHRH to enhance GH secretion and may also reduce the inhibitory effect of somatostatin, thereby amplifying GH release 3. Effect of Nutritional and Metabolic Status o During fasting or caloric restriction, ghrelin levels increase, which enhances GH secretion to mobilize energy stores. o After food intake, ghrelin secretion decreases, leading to lower GH levels. 4. Feedback Regulation o Increased GH or IGF-1 levels can suppress ghrelin secretion, forming a negative feedback loop. o For instance, in GH-deficient patients treated with GH, plasma ghrelin levels were reduced after several months of therapy. Additionally, ghrelin secretion is influenced by body fat mass — GH reduces adiposity, which in turn may lower ghrelin secretion Concluson • Ghrelin serves as a potent stimulator of GH release, particularly under fasting or energy-deficient conditions. • There is a reciprocal feedback between the GH/IGF-1 axis and ghrelin secretion — elevated GH tends to suppress ghrelin release. • In clinical settings, GH therapy alters ghrelin levels and body composition, but responses vary among individuals. • Ongoing research is needed to clarify ghrelin’s full physiological role and its potential as a therapeutic target for metabolic and endocrine disorders. Dr.Ban Dhahir Thabbah Al-Mustaqbal University – Ranked First Among Private Universities