Follicle Stimulating Hormone (FSH)

Follicle Stimulating Hormone (FSH) is a heterodimeric glycoprotein hormone composed of two subunits and vital for reproductive processes. It plays essential roles in ovarian follicular maturation and testicular spermatogenesis. FSH, whether purified from human urine (urofollitropin) or produced recombinantly (follitropin alpha/beta), is used widely in both clinical treatments such as fertility therapy and in basic research. It functions through G-protein coupled receptor pathways and is central to studying reproductive physiology, endocrine disorders, and hormone-responsive cancers.

• Formula (approximate): α-subunit, C₉₆₀H₁₄₉₉N₂₆₃O₂₈₅S₇; β-subunit, C₉₀₇H₁₄₀₈N₂₄₈O₂₇₀S₆
• Molecular weight:~30–35 kDa (heavily glycosylated heterodimeric protein)

• Promotes the growth and maturation of ovarian follicles (primordial -> primary -> secondary -> antral follicles), and stimulates granulosa cell proliferation, increasing follicle size.
• Induces aromatase enzyme in granulosa cells, converting androgens (from theca cells) into estradiol (E₂).
• Involves in the regulation of menstrual cycle.
• Stimulates Sertoli cells to produce androgen-binding protein (ABP), which maintains high testosterone levels in the testes, and then activates spermatogenesis in males via
• Supports nourishment and development of sperm cells (spermatogonia -> spermatocytes -> spermatids).

FSH is also a critical regulator of the hypothalamic-pituitary-gonadal axis.

FSH binds to FSH receptors (FSHR) located on granulosa cells (ovary) or Sertoli cells (testes). FSH-FSHR interaction activates G-protein-coupled receptor signaling, leading to:

• Increasing in cAMP production -> activates protein kinase A (PKA) -> phosphorylation of transcription factors (e. g. CREB) and then
• Increased production of steroidogenic enzymes (aromatase, CYP19A1), grow factors (IGF-1, activin), estrogen, and inhibin, which
• Promotes follicular development and gametogenesis

• Reproductive endocrinology studies (e.g. follicular development, ovulation mechanisms).
• Used in studies aiming at developing variants of assisted reproductive technology (ART) protocols.
• Studies on FSH receptor signaling and mutations, aiding in designing selective agonists/antogonists.
• Research in infertility treatment and hormone replacement therapy.
• Investigations of gonadotropin regulation and feedback mechanisms in the HPG axis.
• Comparative endocrinology in mammals and vertebrates.
• Evaluating the role of FSH in aging, bone metabolism, and certain cancers.

• Sources: purified from human urine (postmenopausal women – urofollitropin)
• Available as almost white to slightly yellowish lyophilized powder
• Store in a sterile, airtight, tamper-proof container, protected from light, at a temperature of 2°C to 8°C