GH1

GH1 Full Name

growth hormone 1

GH1 Introduction

Growth hormone 1 (GH1), encoding the pituitary-derived growth hormone (somatotropin), is the principal member of the human growth hormone gene cluster located on chromosome 17q23.3, which also includes the placental growth hormone variant (GH2) and several chorionic somatomammotropin (CSH) genes. GH1 is expressed specifically in somatotroph cells of the anterior pituitary gland under the transcriptional control of the POU1F1 (Pit-1) transcription factor. The mature 191-amino-acid, 22-kDa protein is the predominant form of circulating growth hormone, an essential endocrine regulator of postnatal somatic growth, metabolism, and body composition.

Figure 1. Strcuture of growth hormone 1.

GH-IGF-1 Axis and Metabolic Regulation
Growth hormone exerts its growth-promoting effects primarily through stimulation of insulin-like growth factor 1 (IGF-1) production in the liver and peripheral tissues — the classical GH-IGF-1 somatomedin axis. GH binding to its receptor (GHR), a member of the class I cytokine receptor superfamily, triggers JAK2 kinase activation and STAT5-mediated transcription of IGF-1 and other target genes. Beyond growth promotion, GH has profound metabolic effects: it stimulates lipolysis in adipose tissue, promotes hepatic gluconeogenesis (counter-regulatory to insulin), and increases amino acid uptake and protein synthesis in muscle. GH secretion from the pituitary is pulsatile and regulated by the counterbalancing hypothalamic peptides growth hormone-releasing hormone (GHRH, stimulatory) and somatostatin (inhibitory), with the stomach-derived peptide ghrelin providing additional stimulation. GH secretion peaks during adolescence and declines progressively with aging (somatopause), contributing to age-related changes in body composition.

GH1 Mutations, Growth Disorders, and Therapeutic Applications
Mutations in the GH1 gene cause isolated growth hormone deficiency (IGHD), a condition characterized by proportionate short stature, delayed bone age, and in severe cases, hypoglycemia in infancy. The most common form (IGHD type IA) results from homozygous deletions of the GH1 gene and is associated with the development of anti-GH antibodies upon recombinant GH treatment. IGHD type IB and II arise from missense or splice-site mutations with varying degrees of GH deficiency. Recombinant human growth hormone (rhGH, somatropin) is used therapeutically for GH deficiency, Turner syndrome, Prader-Willi syndrome, chronic renal insufficiency, and children born small for gestational age. Conversely, excess GH (typically from a pituitary adenoma) causes gigantism in children and acromegaly in adults, treated with somatostatin analogs, GH receptor antagonists (pegvisomant), or surgical adenomectomy. GH1 genetic variation also influences adult height in the general population.

Alternate Names for GH1

gH; GH-N; GH1; GHN; Growth hormone 1; Growth hormone; Growth hormone, normal; Growth hormone, pituitary; HG1; hGH-N; IGHD1B; Pituitary growth hormone; RNGHGP; SOMA_HUMAN; Somatotropin;