Follicle-Stimulating Hormone (FSH) is a peptide hormone primarily involved in reproduction. In females, it stimulates ovarian follicle growth and estrogen production, while in males, it promotes spermatogenesis. FSH is a heterodimer, composed of an alpha and beta subunit, and its interaction with the FSH receptor (FSHR) is crucial for its biological activity. Synthetic peptides corresponding to FSH beta subunit regions, particularly hFSH-β-(33-53) and hFSH-β-(81-95), have been identified as receptor binding sites and are used in research and potential therapeutic applications. 
More Details:
Function:
FSH plays a vital role in regulating the menstrual cycle in women and sperm production in men. 
Structure:
FSH is a glycoprotein hormone composed of two subunits: an alpha subunit (common to other glycoprotein hormones) and a beta subunit that confers receptor specificity. 
Receptor Interaction:
FSH binds to the FSH receptor (FSHR), a membrane protein found on granulosa cells in females and Sertoli cells in males. 
Synthetic Peptides:
Researchers have identified specific regions of the FSH beta subunit, like hFSH-β-(33-53) and hFSH-β-(81-95), that are critical for binding to the FSHR. These regions are used to create synthetic peptides for research purposes. 
Applications:
These synthetic peptides are being investigated for various applications, including:
Targeted drug delivery: FSH peptides can be conjugated to nanoparticles to deliver drugs specifically to ovarian cancer cells or other tissues expressing FSHR. 
Novel FSH pharmacological agents: Synthetic FSH peptides, especially those corresponding to receptor binding sites, are being explored as potential treatments for reproductive disorders or to modulate reproductive processes. 
FSH quantification: Peptides can be used in assays to measure FSH levels in biological samples, which is important for diagnosing reproductive issues.