Chorionic Gonadotropin Hormone

The pituitary hormones, luteinizing hormone (lutropin, LH), chorionic gonadotropin (CG), thyroid stimulating hormone (TSH)  and follicle stimulating hormone (follitropin, FSH) are referred to as glycoprotein hormone/gonadotropic hormones because of their similar structure, glycoprotein composition and action on gonadal cells.  All these hormones are heterodimeric in nature composed of two un-identical subunits, alpha and beta which are non-covalently associated,  Among humans and other species, the Alpha subunit is identical for all these hormones and is coded by a single gene, where is beta subunits are distinct but homologous and arise from separate genes. The individual hormone subunits and peptides derived from them have shown some binding activities to their respective receptors, the association of alpha and beta subunits clearly is required for optimal activation and physiological responses elicited by these hormones.  Within the heterodimeric hormones, the beta subunit confors the binding activity to its respective receptor.  The LH and CG beta subunits have 85% sequence identity in their first 114 amino acids, the LH/CG receptors can recognize either of the pituitary LH or placental CG hormones. 

The alpha and beta subunits of LH, CG and FSH are highly glycosylated (1).  The alpha subunit has two N-linked oligosaccharide chain at position 52 and 78 and beta subunits have one in LH and TSH and two in CG and FSH.  The CG beta subunit also has an extension of serine O-linked carbohydrates at carboxyl end which help is plasma half like of CG compared to other glycol hormone beta subunits.  The N-linked oligosaccharides on FSH are sialylated whereas LH and TSH are sialylated and sulfated.  There are 10-12 cystins forming 3 disulfide bonds referred to as “cystine knots” in each of the beta subunits of these hormones which are conserved in various species.  Adenohypophyseal gonadotroph cells synthesize and secrete LH and FSH under independent regulatory controls and their release by pituitary is positively regulated by hypothalamic decapeptide gonadotropin releasing hormone (GnRH) and is negatively regulated by feedback effects of gonadal steroids and gonadal, peptide inhibin, a peptide produced in testis and ovaries in response to FSH  (2).  Both males and females synthesize and secrete FSH and LH by gonadotrope cells of the anterior pituitary.  In females progesterone and estrogen inhibit LH and FSH release.  The action of LH and CG are carried out by LH/CG receptors and FSH effects are by independent FSH receptors with GPCR associated 7TMDs.

The human chorionic gonadotropin hormone (hCG)-selective antibodies were generated against peptide form unique region near of human CG sequences from beta chain corresponding to region that is common in many species but these sequences are not present in other proteins.  FabGennix Inc. has generated rabbit anti-CG mono-epitope-specific antibodies utilizing linear and cyclic peptide methodology.  The Anti-CG antibodies have been fully characterized for cross reactivity with other species CG molecules and with cellular proteins using Western blot analyses.  The CG antibody is also available as FITC-conjugate, other conjugates can be ordered at a nominal charge.  FabGennix International Inc., has produced antibodies to several other pituitary hormones, for a complete listing please visit www.FabGennix.com.  These and other antibodies, reagents and kits are now available for sale via our worldwide distribution centers.  FabGennix Int. Inc., also provide western blot positive controls and antigenic blocking peptide for this antibody.  Please inquire for pricing and availability. 

For research use only, not for diagnostic or therapeutic use.