Human growth hormone is produced using:
Human growth hormone somatotropin monomeric 22 kDa protein 191 aa two intramolecular disulfide bridges Cys53-Cys165 Cys182-Cys189 secreted somatotrophs anterior pituitary under GHRH stimulates hepatic IGF-1 production promoting longitudinal bone growth protein synthesis. Recombinant production first accomplished E. coli K12 because hormone lacks N-linked glycosylation essential in vivo activity unlike erythropoietin requiring sialylated glycans circulatory half-life, making prokaryotic expression feasible cost-effective. Gene without native signal peptide inserted downstream tryptophan operon
Ref: Endocrine Reviews hGH E coli Production Goeddel 1979; NCBI Biotech hGH Manufacturing Process; Campbell Recombinant Expression Systems Ch 20.