1. A hybrid ligand method for androgen receptor measurement
- Author
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Mjg Farthing, Gavin P. Vinson, Elizabeth Anderson, J.R. Puddefoot, and W. S. L. Stebbings
- Subjects
Male ,medicine.medical_specialty ,medicine.drug_class ,Prostatic Hyperplasia ,Tritium ,Binding, Competitive ,Triamcinolone Acetonide ,Biochemistry ,Cytosol ,Endocrinology ,Sex hormone-binding globulin ,Sex Hormone-Binding Globulin ,Internal medicine ,medicine ,Animals ,Humans ,Estrenes ,Receptor ,False Negative Reactions ,biology ,Rectal Neoplasms ,Uterus ,Prostate ,Dihydrotestosterone ,Rats, Inbred Strains ,Metribolone ,Ligand (biochemistry) ,Androgen ,Molecular biology ,Rats ,Androgen receptor ,High specific activity ,Receptors, Androgen ,Colonic Neoplasms ,biology.protein ,Female ,AR binding ,Orchiectomy ,hormones, hormone substitutes, and hormone antagonists ,medicine.drug - Abstract
Existing techniques for androgen receptor (AR) assay are complicated by cross-reactivity of ligand binding affinities that can lead to incorrect estimation of receptor concentration. Two most frequently used ligands are [3H]dihydrotestosterone [( 3H]DHT) and [3H]methyltrienolone [( 3H]R1881), which in addition to binding to AR also bind to sex hormone binding globulin (SHBG; Kd = 1.5 nM) and progesterone receptors (PgR; Human Kd = 1 nM, rat Kd = 6 nM) respectively. Triamcinolone acetonide (TMA) is commonly used to block binding of [3H]R1881 to PgR, however at high concentrations TMA itself will bind AR (Kd = 7 microM). We have developed a hybrid ligand method for the measurement of AR in the presence of SHBG and PgR. This method used [3H]R1881 as the high specific activity labelled tracer and DHT as the unlabelled competitor of specific AR binding. Using this assay, 20% of human colorectal carcinomas were found to contain AR.
- Published
- 1988
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