Equine follicle-stimulating hormone: Molecular cloning of β subunit and biological role of the asparagine-linked oligosaccharide at asparagine56 of α subunit

T. Saneyoshi, K. S. Min, X. J. Ma, Y. Nambo, T. Hiyama, S. Tanaka, K. Shiota

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Equine FSH (eFSH) and eCG are members of the glycoprotein hormone family. These proteins are heterodimeric, composed of noncovalently associated α and β subunits. We have previously reported that recombinant eCG has potent LH- and FSH-like activities and that the oligosaccharide at Asn16 of the α subunit plays an indispensable role in expressing LH- but not FSH-like activity. In the present study, we cloned eFSH β subunit cDNA and expressed wild-type recombinant eFSH and a partially deglycosylated mutant FSH (eFSH α56/β) to investigate the biological role of the oligosaccharide at Asn16 in FSH activity. The wild-type eFSH and eCG stimulated estradiol production in a dose-dependent manner in the primary cultures of rat granulosa cells, indicating that these equine gonadotropins have FSH activity. Partially deglycosylated eCG (eCG α56/β) also stimulated estradiol production, confirming that the FSH-like activity of eCG is resistant to the removal of the N-linked oligosaccharide. Partially deglycosylated eFSH (eFSH α56/β), however, did not show any FSH activity, indicating that the oligosaccharide at Asn56 was necessary for eFSH. Thus, FSH-like activities of two gonadotropins, eCG and eFSH, are evoked through the distinct molecular mechanisms regarding the biological role of oligosaccharide at Asn56 of the αsubunit.

Original languageEnglish
Pages (from-to)1686-1690
Number of pages5
JournalBiology of Reproduction
Issue number6
Publication statusPublished - 2001
Externally publishedYes



  • FSH
  • Hormone action

ASJC Scopus subject areas

  • Cell Biology
  • Developmental Biology
  • Embryology

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