High serum sex hormone-binding globulin (SHBG) in premature thelarche.
OBJECTIVE
We determined serum sex hormone-binding globulin (SHBG), serum dehydroepiandrosterone sulphate, serum oestradiol and serum testosterone and its fractions in girls with premature thelarche.


METHODS
Blood was drawn from girls with recently diagnosed (3-12 weeks) premature thelarche. Serum was kept frozen for at least one year before hormonal determination to exclude precocious puberty by clinical evaluation.


METHODS
Seventeen girls with premature thelarche aged 0.83-7.16 years were studied, and compared with a group of 22 normal prepubertal girls.


METHODS
SHBG was measured by saturation analysis and serum dehydroepiandrosterone sulphate, serum total oestradiol and serum total testosterone were determined by radioimmunoassay. Non-SHBG-bound testosterone and free testosterone were calculated from an equation derived from the law of mass action.


RESULTS
Median serum SHBG in premature thelarche was 137 nmol/l (range 64-221), significantly higher than in normal controls, 93.7 (32-172) (P < 0.05) non-parametric test of medians. Serum SHBG decreased significantly with age in controls but not in premature thelarche. No difference was found in serum dehydroepiandrosterone sulphate. Median serum total testosterone (0.34 nmol/l, 0.17-0.97), median serum non-SHBG-bound testosterone (0.04 nmol/l, 0.02-0.10) and median free testosterone (2.2 pmol/l, 1.0-4.5) were significantly lower in premature thelarche than in control (P < 0.001).


CONCLUSIONS
Serum SHBG is high and bioavailable T is low in girls with premature thelarche. This might alter the oestrogen/androgen ratio in the breast.
Belgorosky
A
A
Laboratorio de Investigaciones, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
Chaler
E
E
Rivarola
M A
MA
D001940:Breast / Q000254:growth & development*; D002648:Child; D002675:Child, Preschool; D003687:Dehydroepiandrosterone / Q000031:analogs & derivatives / Q000097:blood; D019314:Dehydroepiandrosterone Sulfate; D004958:Estradiol / Q000097:blood; D005260:Female; D006130:Growth Disorders / Q000097:blood*; D006801:Humans; D007223:Infant; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*; D013739:Testosterone / Q000097:blood
D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D003687:Dehydroepiandrosterone; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate