Serum SHBG Research Articles

Sex hormone binding globulin response to testosterone. An androgen sensitivity test.

Adequate distinction between an abnormality in androgen secretion or in target cell response is important in the diagnosis and management of male pseudohermaphroditism. Hormone serum levels give reasonable information on steroid secretion, but there are no simple methods, in clinical practice, to evaluate target cell response to androgens. In this work, we have evaluated the validity of the acute decrease in serum (SHBG) after administration of hCG or exogenous testosterone, as an indicator of androgen sensitivity in prepubertal subjects. The results were expressed as percentage of basal values. In control subjects, after hCG, SHBG dropped below 85% of basal, mean 55 +/- 17, and, after exogenous testosterone, below 80%, mean 62.18 +/- 8.85. In 23 patients studied with the hCG test, 10 positive and 13 negative results were found, but most of the negative responses became positive after exogenous testosterone. Of 25 patients studied with the exogenous testosterone test, 19 positive and 6 negative results were found. Clinical analysis of these 6 patients with negative responses showed that 4 subjects had a confirmed androgen insensitivity syndrome, while clinical information was compatible with this diagnosis in the other 2 patients. Furthermore, in 4 additional patients with the androgen insensitivity syndrome, but with high basal serum testosterone, this test was also negative. It is concluded that determination of serum SHBG after hCG is not reliable as an androgen sensitivity test, but the detection of the decrease in serum SHBG after exogenous testosterone is a useful and simple test of androgen sensitivity.

Dynamics of SHBG response to testosterone. Implications upon the immediate biological effect of sex hormones

The dynamics of the changes in serum concentrations of SHBG to variations in serum testosterone was studied in rabbits. Castration of male rabbits failed to produce changes in SHBG within 2 days but induced a significant increment 2 months later. Administration of 15 mg of testosterone to 5 male castrates produced a rapid decrease in SHBG concentrations from 215 ± 121 nmol/l before, to 114 ± 15. 6 h after (mean ± SD), while 25 mg of the androgen barely changed SHBG levels in 5 females (from 81 ± 26 to 72 ± 22). Three of the males and the 5 females showed a tendency to recover basal levels at 24 and 48 h. Since SHBG is a major regulator of the availability of sex hormones to be transported into tissue cells for both biological action and degradation, the rapid changes in serum SHBG induced by testosterone might play a role in controlling its own biological effect. A decrease in SHBG will result in a more effective stimulation in androgen-responsive tissues, but it will also favor a faster interruption of the effect by increasing the rate of degradation. These androgen induced changes in SHBG are apparently different in male and females.

Sex hormone-binding globulin response to human chorionic gonadotropin stimulation in children with cryptorchidism, anorchia, male pseudohermaphroditism, and micropenis.

Sex hormone-binding globulin serum concentrations (SHBG) were measured before and after a 5-day hCG stimulation test in 11 prepubertal boys with cryptorchidism, 6 with anorchia, 5 with male pseudohermaphroditism, and 5 with micropenis. Cryptorchid boys had decreased SHBG levels after hCG, by 55 +/- 17% (mean +/- SE) of the basal concentration. Patients with anorchia, who did not show an elevation in serum androgens, did not have decreased SHBG concentrations. Four of the 5 patients with male pseudohermaphroditism had an adequate elevation of serum androgens, did not have decreased SHBG concentrations. Four of the 5 patients with male pseudohermaphroditism had an adequate elevation of serum androgens after hCG, but in only 3 of them did SHBG decrease. None of the 5 patients with micropenis had decreased serum SHBG levels despite normal increments in serum androgens. The administration of a long-acting preparation of testosterone to sexually infantile subjects produce a similar decrease in the SHBG concentration. This change in SHBG concentration after hCG or testosterone in prepubertal boys could be used as a convenient test of biological response to androgens.