Somatotropin Long Isoform (human, recombinant)

Somatotropin is a circulating peptide hormone encoded by GH1 in humans that has roles in growth, cellular proliferation and differentiation, muscle and bone anabolism, and lipolysis.¹ Alternative splicing of the GH1 pre-mRNA produces one full-length 22 kDa isoform and a short-length 20 kDa isoform, which has reduced affinity for the somatotropin receptor.² Somatotropin contains a central hydrophobic core and a bundle of four α-helices that forms two somatotropin receptor binding sites.³ It is synthesized and stored by somatotrophs in the anterior pituitary gland and is secreted episodically as a monomer or dimer in a circadian rhythm that peaks during night sleep.^3,2 Somatotropin production is induced by stimulation with growth hormone-releasing hormone, ghrelin, or sex steroids and inhibited by somatostatin, IGF-1, or glucocorticoid stimulation.⁴ Binding of somatotropin to the somatotropin receptor, which is ubiquitously expressed, activates a variety of intracellular signal transduction pathways, including JAK-STAT, that lead to IGF-1, MAPK, PPARγ (Item No. 61700), or SIRPα signaling.^5,1,3 Decreased serum levels of somatotropin have been found in patients with dwarfism.⁶ Increased somatotropin serum levels have been found in patients with acromegaly, a condition characterized by abnormal bone growth, and are positively correlated with early mortality.^6,7 Cayman's Somatotropin Long Isoform (human, recombinant) protein can be used for cell-based assay applications. This protein consists of 212 amino acids and has a calculated molecular weight of 24.7 kDa.

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1. Devesa, J., Almengló, C., and Devesa, P. Multiple effects of growth hormone in the body: Is it really the hormone for growth? Clin. Med. Insights Endocrinol. Diabetes 9, 47-71 (2016).

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3. Ranke, M.B., and Wit, J.M. Growth hormone — past, present and future. Nat. Rev. Endocrinol. 14(5), 285-300 (2018).

4. Lin, S., Li, C., Li, C., et al. Growth hormone receptor mutations related to individual dwarfism. Int. J. Mol. Sci. 19(5), 1433 (2018).

5. Fernández-Pérez, L., Flores-Morales, A., Guerra, B., et al. Growth hormone receptor signaling pathways and its negative regulation by SOCS2. Mol. Endocrinol. 20(2), 241-253 (2016).

6. Murray, R.A., Maheshwari, H.G., Russell, E.J., et al. Pituitary hypoplasia in patients with a mutation in the growth hormone–releasing hormone receptor gene. Am. J. Neuroradiol. 21(4), 685-689 (2000).

7. Kopchick, J.J., List, E.O., Kelder, B., et al. Evaluation of growth hormone (GH) action in mice: Discovery of GH receptor antagonists and clinical indications. Mol. Cell Endocrinol. 386(1-2), 34-45 (2014).