Hypo-glycosylated human follicle-stimulating hormone (hFSH(21/18)) is much more active in vitro than fully-glycosylated hFSH (hFSH(24))
George R Bousfield, Vladimir Y Butnev, Viktor Y Butnev, Yasuaki Hiromasa, David J Harvey, Jeffrey V May, George R Bousfield, Vladimir Y Butnev, Viktor Y Butnev, Yasuaki Hiromasa, David J Harvey, Jeffrey V May
Abstract
Hypo-glycosylated hFSH(21/18) (possesses FSHβ(21) and FSHβ(18)bands) was isolated from hLH preparations by immunoaffinity chromatography followed by gel filtration. Fully-glycosylated hFSH(24) was prepared by combining the fully-glycosylated FSHβ(24) variant with hCGα and isolating the heterodimer. The hFSH(21/18) glycoform preparation was significantly smaller than the hFSH(24) preparation and possessed 60% oligomannose glycans, which is unusual for hFSH. Hypo-glycosylated hFSH(21/18) was 9- to 26-fold more active than fully-glycosylated hFSH(24) in FSH radioligand assays. Significantly greater binding of (125)I-hFSH(21/18) tracer than hFSH(24) tracer was observed in all competitive binding assays. In addition, higher binding of hFSH(21/18) was noted in association and saturation binding assays, in which twice as much hFSH(21/18) was bound as hFSH(24). This suggests that more ligand binding sites are available to hFSH(21/18) in FSHR than to hFSH(24). Hypo-glycosylated hFSH(21/18) also bound rat FSHRs more rapidly, exhibiting almost no lag in binding, whereas hFSH(24) specific binding proceeded very slowly for almost the first hour of incubation.
Keywords: FSH isoforms; FSHR; Oligosaccharide.
Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.
Figures
![Figure 1. Hypo-glycosylated hFSH isolation from hLH…](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/3908837/bin/nihms545309f1.jpg)
![Figure 2. Hypo- and fully-glycosylated hFSH isolation](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/3908837/bin/nihms545309f2.jpg)
![Figure 3. FSH receptor-binding assays of fully-…](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/3908837/bin/nihms545309f3.jpg)
![Figure 4. Saturation binding of hypo- and…](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/3908837/bin/nihms545309f4.jpg)
![Figure 5. Association kinetics for hypo- and…](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/3908837/bin/nihms545309f5.jpg)
![Figure 6. Comparison of recombinant insect hFSH…](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/3908837/bin/nihms545309f6.jpg)
Source: PubMed