Use of post-menopausal serum pool as a reference preparation for RIA of gonadotrophins

A study was undertaken whereby measurements of concentrations of FSH, LH and HCG in serum were performed by a solid phase radioimmunoassay technique utilizing both pituitary (LER-907) and urinary (2nd IRP HMG and 2nd HCG) extracts as well as various serum and plasma pools for reference preparations. These pools were prepared in our laboratory as well as by the MRC. In addition, serial dilutions of these preparations were also measured by RIA. Curves obtained by these serial dilutions were linearized by probit transformation in order to determine parallelism. For LH and FSH, the post-menopausal serum or plasma pools yielded more consistent results than the reference preparations of pituitary or urinary origin indicating both the latter preparations were not satisfactory reference preparations for RIA of gonadotrophins. For HCG either a serum pool obtained from pregnant women or the 2nd HCG were satisfactory reference preparations. Although long term study for the stability of both frozen and lyophilized serum and plasma pools needs to be undertaken, the results of this study have shown during a period of two years that these plasma or serum pools have been a reliable laboratory reference preparation for RIA of gonadotrophins.