Endocrine Abstracts

The glycosyl components of serum gonadotrophins are important determinants of biological half life, receptor binding and bioactivity of these hormones. We have compared serum FSH glycosylation from healthy women with regular ovulatory cycles (group A; n=8) to those identified inpharmacological preparations gonadotrophins (group B merional and group C puregon). Blood samples were taken within 4 days of the onset of menstruation in the control group (group A). Pharmaceutical preparations were diluted in gonadotrophin-free serum to give final concentrations of 10 U/L, comparable to mid-follicular concentrations. After an initial, partial purification step on Superdex-75 pg, FSH was chromatographed on immobilised lectins, ConA and WGA, eluted with mannose or N-acetyl glucosamine (GlcNAc) respectively. Chromatography fractions were assayed for FSH content using a commercially available platform from Roche. Eluted FSH was divided into 1 unbound, (batch 1), and 7 bound batches (weakly bound; batch 2 through to strongly bound batch 8). Elution profiles for groups B and C were compared to group A by Mann Whitney U test, from which z values were derived, a z value >1.96 being significant at the 95% (P=<0.05) level. When compared with women in group A, FSH from group B (merional) showed significantly different ConA binding in batches 5, 6, 7 & 8 (z=4.3, 4.85, 4.83 & 4.85) and WGA binding in batches 5 & 8 (z=3.2 and 3.06). By ConA chromatography, group C (puregon) differed from group A in batches 1, 3, 6 & 8 (z=2.83, 2.33, 2.13 & 2.58 respectively) and by WGA in batches 1, 6, 7 & 8 (z=2.62, 2.45, 3.76 & 3.21) Preparations of FSH currently used for ovulation induction are associated with serum FSH glycosyl structures that differ significantly from physiological patterns of glycosylation seen in follicular phase FSH from healthy, ovulatory women.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.