The International Reference Preparation of Gonadorelin for Bioassay: a comparison with different preparations of synthetic luteinizing hormone releasing hormone using physicochemical methods of analysis, different bioassays and immunoassay.
The preparation and nature of the International Reference Preparation of Gonadorelin for Bioassay (IRP; coded 77/596) are described. The IRP was studied by four laboratories in four countries and compared, using physicochemical methods of analysis, various bioassay procedures and immunoassay, with preparations of synthetic luteinizing hormone releasing hormone (LH-RH) produced by different manufacturers. Analyses by thin-layer chromatography and by reverse-phase high-performance liquid chromatography (HPLC) indicated some heterogeneity of the peptide present in most of these preparations of synthetic LH-RH, including that of the IRP; the latter preparation appeared to be 88.3% (w/w) pure, judged by HPLC. The data from the collaborative study suggested that each ampoule of the IRP contains approximately 31 nmol LH-RH. The IRP appeared to be suitable to serve as an international reference preparation for bioassay since its behaviour was similar in different bioassays, so far as this could be examined, to that of the other preparations of LH-RH with which it was compared. Furthermore, the biological activities of different preparations of LH-RH, assessed in terms of the IRP, appeared to correlate with their degrees of purify assessed by physicochemical methods, suggesting that the peptides other than LH-RH present in the IRP did not contribute significantly to the biological activity of the preparation in these assay procedures. The limited data available suggested that the IRP might also be suitable as a reference preparation for immunoassay. The ampouled preparation, coded 77/596, was therefore established by the World Health Organization as the International Reference Preparation of Gonadorelin for Bioassay and assigned a unitage of 31 i.u./ampoule on the basis that the i.u. is represented by 1 nmole of LH-RH.
D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000592:standards*; D006728:Hormones / Q000592:standards*; D007118:Immunoassay; D010053:Ovary; D012015:Reference Standards; D013056:Spectrophotometry, Ultraviolet
D006728:Hormones; D007987:Gonadotropin-Releasing Hormone