Radiolabeled steroid derivatives having the formula ##STR1## wherein St is des-hydroxy steroid moiety of (i) a hydroxy steroid intended for radioimmunoassay or (ii) a hydroxy containing derivative of a steroid intended for radioimmunoassay, said derivative having a strong affinity for the antibodies of the steroid intended for radioimmunoassay; R is hydrogen or alkyl of 1 to 3 carbon atoms; n is 0, 1, 2, 3 or 4 and the asterisk (*) indicates tagging with a radioisotope, are useful as tracers in radioimmunoassays.
具有以下公式的放射性标记类
固醇衍
生物 ##STR1## 其中ST是(i)用于放射免疫测定的羟基类
固醇的去氢类
固醇基团,或者(ii)用于放射免疫测定的类
固醇的含羟基衍
生物,该衍
生物对于放射免疫测定的类
固醇的
抗体具有很强的亲和力;R为氢或1至3个碳原子的烷基;n为0、1、2、3或4,星号(*)表示与放射性同位素标记,可用作放射免疫测定中的示踪剂。