Recombinant Human Growth Hormone

Recombinant human growth hormone (rhGH) is used in research applications because it is a bioactive, standardized form of human growth hormone that enables controlled studies of growth, metabolism, and tissue regeneration, and is essential for modeling and treating growth hormone deficiency and related disorders.

Key reasons to use rhGH in research include:

• Consistency and Purity: Recombinant production ensures a highly pure, consistent product, minimizing batch-to-batch variability and eliminating the risk of contamination associated with pituitary-derived GH.
• Mechanistic Studies: rhGH is critical for investigating the physiological roles of growth hormone, including its effects on linear growth, bone metabolism, protein synthesis, fat metabolism, and cardiovascular function.
• Disease Modeling: It is widely used to model and study conditions such as growth hormone deficiency (GHD), idiopathic short stature (ISS), Turner syndrome, Prader-Willi syndrome, and other genetic or acquired disorders affecting growth and metabolism.
• Therapeutic Evaluation: rhGH allows for preclinical and clinical evaluation of dosing regimens, efficacy, and safety in various populations, including children and adults with GHD, as well as in metabolic and aging studies.
• Biomarker and Pathway Analysis: Its use enables the study of downstream mediators such as insulin-like growth factor 1 (IGF-1), IGF binding proteins, and other molecular pathways involved in growth and tissue repair.
• Metabolic Research: rhGH is used to study its impact on body composition, including increases in lean body mass, reductions in fat mass, and effects on glucose and lipid metabolism.
• Regenerative Medicine: Research applications include exploring rhGH’s role in tissue regeneration, wound healing, and recovery from catabolic states.

In summary, recombinant human growth hormone is a fundamental tool in biomedical research for elucidating growth hormone biology, modeling disease, and developing and testing new therapies in a reproducible and clinically relevant manner.

Yes, recombinant human growth hormone (rhGH) can be used as a standard for quantification or calibration in ELISA assays, provided it is well-characterized and compatible with your assay system. This is a common practice in both research and clinical settings.

Supporting details:

• Parallelism and Quantification: Studies and commercial ELISA kits demonstrate that E. coli-expressed recombinant human growth hormone produces standard curves that are parallel to those generated with natural human growth hormone, indicating that rhGH is suitable for quantification and calibration in ELISA assays. This parallelism is essential for accurate quantification, as it means the recombinant standard behaves similarly to the endogenous analyte in the assay.

• Validation in Published Protocols: Published ELISA protocols and kit instructions routinely use recombinant hGH as the standard for generating calibration curves. Analytical recovery, linearity, and precision data confirm that rhGH standards yield accurate and reproducible results in the quantification of hGH in biological samples.

• Assay Compatibility: Most sandwich ELISA kits for human growth hormone are designed to detect both natural and recombinant forms of the protein, as long as the recombinant protein is full-length and properly folded. The specificity of the antibodies used in the assay is critical—if the antibodies recognize epitopes present on the recombinant protein, it will serve as a valid standard.

• Best Practices:

  • Ensure the recombinant standard is of high purity and its concentration is accurately determined.
  • Prepare fresh standard dilutions for each assay to avoid degradation or adsorption losses.
  • Confirm that the recombinant standard matches the isoform and post-translational modification state (if relevant) of the endogenous hormone in your samples, as rare differences could affect antibody recognition in some assays.

• Limitations: If your ELISA uses antibodies that are highly specific for certain post-translational modifications or isoforms not present in your recombinant standard, this could affect quantification. Always check the assay's documentation or validate the standard curve with your specific recombinant protein.

In summary: Recombinant human growth hormone is widely accepted and validated as a standard for ELISA quantification and calibration, as long as it is compatible with the antibodies and detection system used in your assay.

Recombinant human growth hormone (rhGH) has been validated in published research for a range of clinical and experimental applications, primarily related to growth disorders and metabolic regulation.

Key validated applications include:

• Pediatric Growth Disorders:

  • Growth hormone deficiency (GHD) in children: rhGH is extensively validated for stimulating linear growth and improving final adult height in children with GHD.
  • Turner syndrome: Used to treat short stature associated with this chromosomal disorder.
  • Chronic renal insufficiency/end-stage renal disease: Applied to manage growth failure in affected children.
  • Noonan syndrome and idiopathic short stature (ISS): Shown to increase growth velocity and improve height outcomes.

• Adult Indications:

  • Adult growth hormone deficiency: rhGH is validated for improving body composition, bone density, and quality of life in adults with confirmed GHD.
  • AIDS-associated wasting: Used to counteract severe weight loss and muscle wasting in HIV/AIDS patients.

• Other Clinical Research Applications:

  • Traumatic brain injury (TBI) rehabilitation: Investigated for its potential to enhance neuroregeneration and functional recovery in the subacute phase after TBI.
  • Metabolic regulation: Studies have assessed rhGH’s effects on insulin-like growth factor-1 (IGF-1) and related metabolic parameters in both children and adults.

• Preclinical and Experimental Uses:

  • Animal models: rhGH and its long-acting or PEGylated forms have been validated in rodent and primate models for dose-response, pharmacokinetics, and safety studies related to GHD and metabolic effects.

• Adherence and Treatment Optimization:

  • Digital health interventions: Research has validated the use of smartphone apps to improve adherence to rhGH therapy in pediatric populations.

Summary Table: Validated Applications of Recombinant Human Growth Hormone

Additional Notes:

• rhGH is also under investigation for other off-label and experimental uses, but the above represent the most robustly validated applications in published research.
• Safety, dosing, and long-term outcomes are active areas of ongoing research and clinical trials.

If you require details on a specific application, protocol, or experimental context, please specify for a more targeted summary.

To reconstitute and prepare Recombinant Human Growth Hormone (rHGH) for cell culture experiments, follow these best practices based on scientific protocols and manufacturer recommendations:

1. Reconstitution of Lyophilized rHGH

• Centrifuge the vial briefly before opening to ensure all lyophilized powder is at the bottom.
• Reconstitute with an appropriate buffer:
  • Use 10 mM sodium phosphate buffer (pH 8.0) or 10 mM NH₄HCO₃ (pH 8.0) for initial solubilization, as recommended for many recombinant proteins.
  • Alternatively, sterile distilled water or a buffer specified in the product’s Certificate of Analysis (COA) or technical manual may be used.
• Add the diluent slowly:
  • Gently add the required volume of buffer to the vial, directing the pipette or syringe against the vial wall to minimize foaming.
  • Avoid vigorous shaking; instead, gently swirl or tap the vial to dissolve the powder.
  • Allow the solution to sit at room temperature for 15–30 minutes with gentle agitation if needed.

2. Preparation for Cell Culture

• Dilute to working concentration:
  • After reconstitution, further dilute the rHGH in cell culture medium or an appropriate buffer (e.g., PBS or serum-free medium) to the desired concentration for your experiment.
  • Typical working concentrations for cell culture range from 1–100 ng/mL, depending on the cell type and experimental design.
• Adjust pH if necessary:
  • Ensure the final solution is at physiological pH (~7.4) before adding to cells.
• Sterile filtration (optional):
  • If not already sterile, filter the solution through a 0.22 µm filter before adding to cell cultures.

3. Storage and Handling

• Short-term storage:
  • Store reconstituted rHGH at 4°C for up to 2–7 days.
• Long-term storage:
  • For longer storage, aliquot and freeze at –20°C or –80°C.
  • Add 0.1% HSA or BSA to prevent adsorption and degradation.
  • Avoid repeated freeze-thaw cycles.

4. Quality Control

• Confirm protein identity and activity using appropriate assays (e.g., ELISA, bioassay, or cell proliferation assay).
• Monitor for contamination and aggregation, especially after reconstitution.

Summary Protocol

1. Centrifuge lyophilized rHGH vial.
2. Reconstitute with 10 mM sodium phosphate buffer (pH 8.0) or as specified.
3. Gently mix; do not vortex.
4. Dilute in cell culture medium to desired concentration.
5. Adjust pH to 7.4 if needed.
6. Filter sterilize if required.
7. Use immediately or store appropriately.

Always refer to the product-specific datasheet or COA for exact reconstitution and handling instructions, as protocols may vary slightly between suppliers and expression systems.