GHS

Growth hormones (GHs) are a family of peptide hormones produced primarily by the anterior pituitary gland in mammals. The best known member is growth hormone, or somatotropin, which acts on multiple tissues to regulate growth, metabolism, and body composition. GHs vary across species but share a common mechanism of action through binding to the growth hormone receptor (GHR). In humans, the liver is a major secondary site of action, producing insulin-like growth factor 1 (IGF-1) in response to GH stimulation.

Mechanism of action: GHs bind to GHRs, activating intracellular signaling pathways (notably JAK2-STAT). This stimulates IGF-1 production, which mediates many growth-promoting effects. GHs also have direct actions on bone, muscle, adipose tissue, and other organs, influencing protein synthesis, lipid mobilization, and carbohydrate metabolism.

Physiological roles: In children, GHs support linear growth and organ development. In adults, they help maintain lean mass, bone density, and metabolic balance. GHs promote lipolysis, alter glucose handling, and influence tissue repair.

Regulation: GH secretion is pulsatile and governed by hypothalamic hormones and other factors. Growth hormone-releasing hormone (GHRH) stimulates release, while somatostatin inhibits it. Ghrelin, sleep, exercise, and nutrition modulate secretion. IGF-1 provides negative feedback to reduce GH release.

Clinical relevance: GH deficiencies result in short stature and delayed development; treatment with recombinant human growth hormone is common for several pediatric and adult growth disorders. Excess GH, typically from pituitary tumors, causes acromegaly in adults and gigantism in children. GH therapies require monitoring for efficacy and adverse effects, including joint discomfort, edema, insulin resistance, and rare metabolic complications. GHs remain an important area of endocrinology and sports medicine, with ongoing research into dosing, safety, and alternatives.