Question 1

What is Human Growth Hormone?

Accepted Answer

Human Growth Hormone (hGH, somatotropin) is a 191-amino acid polypeptide hormone secreted by somatotroph cells of the anterior pituitary gland. It is the master anabolic hormone regulating growth, body composition, metabolism, and tissue repair throughout life. Recombinant hGH (rhGH) was one of the first therapeutic proteins produced using genetic engineering (Genentech, 1985) and revolutionized treatment of growth disorders. hGH acts both directly through the GH receptor and indirectly through stimulation of hepatic IGF-1 production. It promotes longitudinal bone growth in children, increases lean muscle mass, reduces adiposity (particularly visceral fat), enhances bone mineral density, and supports immune function. Approved indications include pediatric GH deficiency, Turner syndrome, Prader-Willi syndrome, adult GH deficiency, AIDS-related wasting, and short bowel syndrome.

Question 2

How does Human Growth Hormone work?

Accepted Answer

hGH binds to the GH receptor (GHR) — a type I cytokine receptor — on target cells, causing receptor dimerization and activation of the JAK2 tyrosine kinase. JAK2 phosphorylates STAT5b (the primary GH signaling mediator), STAT1, and STAT3. Nuclear STAT5b drives IGF-1 gene transcription in liver and other tissues. GH also directly activates MAPK/ERK (cell proliferation), PI3K/Akt (metabolic effects), and SRC kinases. Direct GH effects include lipolysis in adipose tissue, protein synthesis in muscle, and sodium/water retention in kidneys.

Question 3

What are the research applications of Human Growth Hormone?

Accepted Answer

Pediatric Growth Disorders (Approved)

FDA-approved for GH deficiency, Turner syndrome, Prader-Willi syndrome, SGA, idiopathic short stature, Noonan syndrome, and SHOX deficiency.

Adult GH Deficiency (Approved)

FDA-approved for adult GHD showing improved body composition, bone density, cardiovascular risk profile, and quality of life.

Anti-Aging Research

Controversial use for age-related GH decline. TRIIM trial demonstrated thymic regeneration and epigenetic age reversal in healthy men treated with GH + DHEA + metformin.

AIDS Wasting (Approved)

FDA-approved (Serostim) for HIV-associated wasting and cachexia.

Question 4

What are the biological pathways affected by Human Growth Hormone?

Accepted Answer

GHR/JAK2/STAT5b for IGF-1 production. GHR/MAPK/ERK for cell proliferation. GHR/PI3K/Akt for glucose uptake (acute) and insulin resistance (chronic). GHR/SRC for metabolic regulation. Direct lipolytic pathway via HSL/ATGL activation in adipocytes.

Question 5

What are the potential side effects of Human Growth Hormone?

Accepted Answer

Fluid retention (edema), arthralgia, carpal tunnel syndrome, insulin resistance/hyperglycemia, headache. In children: slipped capital femoral epiphysis, progression of scoliosis, intracranial hypertension. Long-term concerns about potential cancer risk (IGF-1 is a growth factor), though clinical data is reassuring for approved indications. Acromegalic features with chronic supraphysiological dosing.

Research Use Only. This information is for educational and research purposes only. Not intended for medical advice or self-medication.

Question 6

How should Human Growth Hormone be stored?

Accepted Answer

Recombinant hGH is supplied as lyophilized powder or liquid formulations. Store at 2-8°C (liquid) or room temperature (lyophilized, depending on formulation). Long-acting formulations (somapacitan, lonapegsomatropin) provide weekly dosing. Sensitive to shaking, heat, and freezing. hGH is a protein — not a small peptide — requiring careful handling.

Question 7

What is the regulatory status of Human Growth Hormone?

Accepted Answer

FDA-approved under multiple brand names: Genotropin, Humatrope, Norditropin, Nutropin, Saizen, Serostim, Zomacton, Sogroya (long-acting). Controlled substance (Schedule III in some US states). WADA-prohibited under S2. Available by prescription only.

Question 8

Where can I find research studies on Human Growth Hormone?

Accepted Answer

Scientific studies on Human Growth Hormone can be found in peer-reviewed journals through databases like PubMed and Google Scholar.

Question 9

What quality standards should Human Growth Hormone meet for research?

Accepted Answer

Research-grade Human Growth Hormone should meet high purity standards, typically >95% purity, with proper analytical certification and storage requirements.

Human Growth Hormone