Human chorionic gonadotrophin contributes to the bioactivity of Pergonal.
OBJECTIVE
We examined batch variation in the LH-like bioactive content of Pergonal and determined whether hCG contributes to this.


METHODS
Random selection of three batches of Pergonal, consisting of three ampoules in each batch.


METHODS
The LH content in each ampoule was determined by radioimmunoassay (R-LH), immunoradiometric assay (I-LH) and in vitro Leydig cell bioassay (B-LH) using the urinary hMG International Standard 70/45. Human chorionic gonadotrophin was determined by immunoradiometric assay (I-hCG) using the hCG IRP 75/537. The isohormone content of each batch was examined by chromatofocussing over the range pH 4.5-7.0 and the fractions collected were assayed for LH and hCG content. The variability in potency between batches was assessed by single factor analysis of variance.


RESULTS
The gonadotrophin content of each batch (IU/ampoule, mean +/- SEM, n = 3 ampoules) was R-LH (40.9 +/- 0.5, 40.8 +/- 0.2, 39.3 +/- 0.7, P > 0.15), I-LH (39.0 +/- 1.5, 28.3 +/- 0.8, 36.9 +/- 3.3, P < 0.001), B-LH (27.3 +/- 0.3, 12.0 +/- 0.9, 19.3 +/- 0.9, P < 0.001) and I-hCG (16.4 +/- 0.7, 11.7 +/- 0.2, 10.5 +/- 0.5, P < 0.001). The chromatofocussing recoveries below pH 5.5 expressed as a percentage of the total amount of analyte eluted from the column and collated for all three batches of Pergonal were (mean % +/- SD, n = 3 batches) R-LH (58.4 +/- 4.0), I-LH (41.3 +/- 7.5), B-LH (81.4 +/- 2.8) and I-hCG (87.8 +/- 3.7).


CONCLUSIONS
There was significant batch variation in the I-LH, B-LH and I-hCG (P < 0.001) but not the R-LH (P > 0.15) content of Pergonal. More than 80% of the total B-LH recovery chromatofocussed below pH 5.5 and corresponded to the region of highest I-hCG (> 87%) and lowest I-LH (< 42%) recovery. This was highly suggestive of hCG contributing to the LH-like bioactivity of Pergonal.
Rodgers
M
M
Department of Clinical Biochemistry, Hope Hospital, Salford, UK.
Mitchell
R
R
Lambert
A
A
Peers
N
N
Robertson
W R
WR
D006063:Chorionic Gonadotropin / Q000032:analysis*; D004340:Drug Contamination; D005260:Female; D006801:Humans; D007986:Luteinizing Hormone / Q000032:analysis* / Q000494:pharmacology; D008596:Menotropins / Q000737:chemistry / Q000494:pharmacology*; D010053:Ovary / Q000187:drug effects*; D013268:Stimulation, Chemical
D006063:Chorionic Gonadotropin; D008596:Menotropins; D007986:Luteinizing Hormone