Characteristics of anti-testosterone antisera produced by bovine serum albumin conjugates of 15 alpha- and 15 beta-carboxymethyltestosterone: use of [125I]iodinated tracers

Each testosterone 125I]iodinated histamine derivative where 125I]iodinated histamines were linked to respective 15 alpha- and 15 beta-carboxymethyltestosterone (15 alpha- and 15 beta-CMT), testosterone-3-(O-carboxymethyl)oxime (T-3-CMO) and testosterone-17 beta-hemisuccinate (T-17-HS) were tested for their usefulness as radiotracers in testosterone immunoassay. In the use of anti-15 alpha- and 15 beta-CMT antisera produced in rabbits against 15 alpha- and 15 beta-CMT-bovine serum albumin (BSA) conjugates, the antisera with 15 alpha- and 15 beta-CMT-125I]iodinated tracers showed low sensitivity and somewhat low specificity in comparison with those of the antisera with tritiated testosterone (T-3H). On the other hand, the antisera with T-3-CMO-125I]iodinated tracer showed high sensitivity but low specificity for 5 alpha-dihydrotestosterone (5 alpha-DHT) in comparison with T-3H. The T-17-HS-125I]iodinated tracer was not bound to the antisera. In the use of anti-15 alpha- and 15 beta-CMT antisera produced in rabbits by pretreatment with 15 alpha-carboxymethyl-5 alpha-DHT linked to a copolymer of D-glutamic acid and D-lysine followed by immunization with 15 alpha- and 15 beta-CMT-BSA, the antisera with homologous 125I]iodinated tracer showed high sensitivity and specificity.