Growth Hormone Protein 20 kDa (Human) – Research Use Only

Scientific Overview

The 20 kDa human Growth Hormone (20K hGH) is a naturally occurring isoform of pituitary growth hormone produced through alternative splicing of the GH1 gene. Although closely related to the predominant 22 kDa isoform, the 20 kDa variant exhibits distinct biochemical behavior, receptor interactions, and internalization characteristics. These differences make it a valuable molecular tool for studying GH receptor biology, isoform-specific signaling, and GH pathway regulation.

Common Research Applications

• Studies of GH receptor binding, affinity, and dimerization
• Isoform-specific GH signaling investigations
• Biochemical assays requiring purified GH protein
• Protein–protein interaction studies involving GH or GH receptor domains
• Mass spectrometry method development for GH isoform differentiation
• Cell-based research involving GH-responsive pathways (RUO)

Usage & Handling Guidance

This product is supplied as a 1 mg/mL solution. Researchers typically dilute GH proteins in PBS, Tris-based buffers, or assay-specific formulations. To maintain structural integrity, mix gently and avoid vigorous agitation. Upon receipt, aliquot to prevent repeated freeze–thaw cycles.

• Recommended storage: -20°C
• Thawing: thaw on ice and mix gently
• Avoid: repeated freeze–thaw cycles and extended exposure to room temperature

Research Background

Published studies demonstrate that the 20 kDa GH isoform differs from the 22 kDa form in receptor binding behavior, internalization kinetics, and downstream signaling profiles. Some reports show that 20K hGH can stimulate IGF‑I gene expression at lower concentrations in GH receptor–expressing cell lines, while other studies highlight differences in receptor site engagement and isoform-specific biological responses. These characteristics make the 20 kDa isoform a useful tool for dissecting GH pathway specificity and isoform-dependent mechanisms.

What You Get

• 100 µg purified 20 kDa human Growth Hormone protein
• 1 mg/mL solution in biotechnology-grade buffer
• Sterile-filtered (0.22 μm)
• Prepared using Type I ultrapure water
• For research use only (RUO)

Frequently Asked Questions

• Is this product suitable for clinical or diagnostic use? No. This product is for research use only.
• Is this the same as the 22 kDa GH isoform? No. The 20 kDa isoform is an alternative splice variant with distinct biochemical properties.
• Can I obtain a Certificate of Analysis (COA) or Technical Data Sheet (TDS)? COA and TDS availability depends on the manufacturer’s current active batch. In many cases, documentation can be provided upon request. Please contact us to inquire about documentation for the specific lot being shipped.
• Can this be used in cell-based assays? Researchers commonly use GH proteins in GH-responsive cell systems for research purposes.

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References

• Stokman M, Lilien M, Knoers N. Nephronophthisis 2016 Jun 23. In: Adam MP, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews(®) [Internet]. Seattle (WA): University of Washington, Seattle; 1993–2022.
• Hai-Nan L, Hui-Lin L, Zi-Qi Z, Gan L, Xue-Qi F, Xin Z. Cellular internalization and trafficking of 20 KDa human growth hormone Gen Comp Endocrinol. 2019 Jan 1;270:82-89.
• Such-Sanmartín G, Bache N, Bosch J, Gutiérrez-Gallego R, Segura J, Jensen ON. Detection and differentiation of 22 kDa and 20 kDa Growth Hormone proteoforms in human plasma by LC-MS/MS Biochim Biophys Acta. 2015 Apr;1854(4):284-90.
• Livingstone C. IGF2 and cancer Endocr Relat Cancer. 2013 Oct 24;20(6):R321-39.
• Uchida H, Banba S, Wada M, Matsumoto K, Ikeda M, Naito N, Tanaka E, Honjo M. Analysis of binding properties between 20 kDa human growth hormone (hGH) and hGH receptor (hGHR): the binding affinity for hGHR extracellular domain and mode of receptor dimerization J Mol Endocrinol. 1999 Dec;23(3):347-53.
• Yoshizato H, Tanaka M, Fujikawa T, Higashimoto Y, Shimizu A, Nakashima K. 20 kDa human growth hormone (20K hGH) stimulates insulin-like growth factor-I (IGF-I) gene expression at lower concentrations than 22K hGH in hGH receptor-expressing Ba/F3 cells Endocr J. 2000 Mar;47 Suppl:S37-40.
• Longhi SA, Cortés MM, Retegui LA. 22- and 20 kDa-human growth hormones bind to different sites within certain cellular receptors Growth Horm IGF Res. 2003 Dec;13(6):353-60.
• Hansen BS, Hjorth S, Welinder BS, Skriver L, De Meyts P. The growth hormone (GH)-binding protein cloned from human IM-9 lymphocytes modulates the down-regulation of GH receptors by 22- and 20-kilodalton human GH in IM-9 lymphocytes and the biological effects of the hormone in Nb2 lymphoma cells Endocrinology. 1993 Dec;133(6):2809-17.
• Arsene C, Schulze D, Röthke A, Thevis M, Henrion A. Growth hormone isoform-differential mass spectrometry for doping control purposes Drug Test Anal. 2018 Jun;10(6):938-946.