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Physiological oestradiol administration does not change the biological to immunological ratio of LH in serum from post‐menopausal women
Author(s) -
Buckler H. M.,
Rothwell C.,
Holds S.,
Robertson W. R.
Publication year - 1993
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1993.tb00343.x
Subject(s) - radioimmunoassay , endocrinology , medicine , progestogen , basal (medicine) , bioassay , serum concentration , gonadotropin , luteinizing hormone , chemistry , hormone , biology , insulin , genetics
Summary OBJECTIVE We Investigated the effect of chronic physiological concentrations of oestradiol on the bioactivity (B) and immunoactivity (I) of LH in serum using radioimmunoassay (RIA) and a sensitive Immunoradlometrlc (IRMA) assay. DESIGN Twelve post‐menopausal, hysterectomized women received a 50‐mg subcutaneous E2 Implant, in the absence of progestogen treatment. Pretreatment serum samples were obtained on two occasions for measurement of E 2 and FSH by radioimmunoassay and for measurement of LH by bioassay (BIO), immunoradio‐metric assay and radioimmunoassay. Further serum samples were obtained monthly for 6 months for assay as above. RESULTS The serum E 2 level (basal levels< 70 pmol/l) rose following implant ( P <0.01) peaking at 1 month (mean 454, range 356–580 pmol/l) and remaining within premenopausal physiological levels for 6 months. There were falls in FSH, LH‐RIA, LH‐IRMA and LH‐BIO ( P < 0.001). There was no change in the B:I ratio for B:I‐RIA or B:I‐IRMA for LH which were 1.8 and 3.3, respectively pretreatment and 1.7 and 2.9 after 1 month's treatment. CONCLUSION The treatment of post‐menopausal women with 50‐mg E 2 subcutaneous implants produces physiological premenopausal E 2 levels for at least 6 months. There is no change In the B:I ratio of LH using either the RIA or IRMA during chronic E2 treatment.