Characterisation of gonadotrophin preparations used in assisted reproduction.

Gonadotrophin preparations are integral to assisted reproduction programmes and in this thesis their structural, biological and immunological content was characterised. Serum LH-like bioactivity in patients treated with Pergonal was examined. LH content in Pergonal was measured between batches using radioimmunometric (R), immunoradiometric (I) and in-vitro biological (B) assays; hCG was determined by immunoradiometric assay (I-hCG). The isoform distribution of R-LH, I-LH, B-LH and I-hCG was determined following chromatofocussing. R-LH content was similar (39.3 - 40.9 IU/ampoule), but I-LH (28.2 - 39.3, p 0.00l) and B-LH (11.9 - 27.6, p 0.001) levels were markedly different. Variable quantities of I-hCG were present (10.5 - 16.4 IU/ampoule), a finding confirmed by its acidic isoform distribution. Ten patients treated with Pergonal over cycle days 5 to 10 had serum LH/hCG levels measured by B-LH, fluoroimmunometric (D)-LH and D-hCG assays. D-hCG and B- LH levels rose from 0.4 - 1.2 IU/L and 11.7 - 16.6 IU/L over days 5 to 8 concomitant with Pergonal administration. D-LH levels remained unchanged. R- and B-FSH levels (IU/ampoule) varied for Metrodin (34.9 - 63.9 and 78.8 - 108 respectively) and Pergonal (46.8 - 60.6 and 34.8 to 70.0 respectively). The FSH B:R ratio of Metrodin was 4 times higher than Pergonal suggesting the isoforms of FSH in Metrodin had higher bioactivity. Isoforms of recombinant FSH (recFSH) were similar to those of Metrodin and hMG (IS 70/45) with 80-93% having a pi 3.5 - 7.0; pituitary FSH (IS 83/575) had 71 % of the isoforms with a pI 3.5. The biopotency of recFSH was two and four times higher than Metrodin and IS 83/575 respectively. In conclusion (1) there is marked batch variation in the gonadotrophin content of Pergonal and Metrodin (2) Pergonal contains hCG which contributes to LH-like bioactivity in patients undergoing treatment; inappropriate levels of LH are associated with impaired fertility and increased risk of miscarriage (3) isoforms in recFSH are similar to those in urinary but dissimilar to those in pituitary FSH preparations.