Relationship between serum testosterone and sex hormone-binding globulin in adult men with intact or absent gonadal function.

Serum levels of testosterone and sex hormone-binding globulin (SHBG) were determined in 80 apparently healthy men aged 25-85 years and in 23 patients with prostatic carcinoma (CAP) aged 60-75 years before and 6 months after orchidectomy. Serum levels of testosterone and SHBG were correlated positively in healthy men, in all subjects overall as well as within different age groups, and in CAP patients before, but not after, orchidectomy. These data are not consistent with the classical theory regarding SHBG regulation and also speak against an influence of SHBG binding on testosterone metabolism as a mechanism behind the observed positive association between testosterone levels and SHBG.