A method for the preparation of steroid-protein antigens for the use in immunoassay of steroids

A general method for the preparation of steroid-protein conjugates coupled through carbon 6 of Δ⁴ steroids was demonstrated using 6β Br-testosterone acetate and 6β Br-progesterone covalently bound to sulfhydryl-group-enriched bovine serum albumin. The antigenicity of the conjugates and the specificity of the antibodies were evaluated. With anti-progesterone the assay accuracy was determined to be 10.3%, the intra-assay precision was 8.7% and the inter-assay precision was 12.6%. The material was used to assay the progesterone content of normal human male and female serum as well as the changes in this hormone following corpora lutea induction in constant-estrus androgenized female rats.