HGH Fragment 176-191 Peptide

HGH 191AA (Somatotropin) is recombinant human growth hormone consisting of 191 amino acids in a single polypeptide chain with two disulfide bonds. It is structurally identical to endogenous pituitary-derived growth hormone, which is the most abundant anterior pituitary hormone. Growth hormone is synthesized, stored, and secreted by somatotroph cells within the anterior pituitary gland. Its secretion follows a pulsatile pattern regulated by the opposing actions of GHRH (stimulatory) and somatostatin (inhibitory). Published research has extensively characterized its receptor binding, signaling cascades, and downstream effects. For laboratory research use only.

GH Receptor (GHR) Activation GH binds to the growth hormone receptor (GHR), a type I cytokine receptor. GH binding induces receptor dimerization, bringing two intracellular JAK2 kinase molecules into proximity. This triggers JAK2 trans-phosphorylation and activation, which subsequently phosphorylates STAT5a/5b transcription factors. JAK2-STAT5 Signaling The JAK2-STAT5 pathway is the primary signaling cascade for GH action. Phosphorylated STAT5 dimerizes and translocates to the nucleus, where it activates transcription of target genes including IGF-1, the principal mediator of many GH effects. This GH-IGF-1 axis is fundamental to growth physiology. MAPK and PI3K Pathways Beyond STAT5, GH activates additional signaling cascades including the MAPK/ERK pathway (cell proliferation) and PI3K/Akt pathway (metabolic effects, cell survival). These pathways mediate the diverse metabolic effects of GH including lipolysis, glucose regulation, and protein synthesis.