Sex hormone binding globulin decrease as a potential pathogenetic factor for hirsutism in adolescent girls

We investigated 252 non-obese female subjects aged 13-39 years to evaluate if an exaggerated descent of sex hormone binding globulin (SHBG) levels during adolescence can play a role in the development of hirsutism. Body hair was assessed according to Ferriman and Gallwey (FG), with a stringent criterion of normality of < or = 4. In 13-14 years girls, SHBG and free testosterone (FT) levels were similar in "hirsute" girls (FG > 4) and controls (FG < or = 4, regular menstrual cycles, no acne). In 15-18 years girls, SHBG values were lower in "hirsute" girls, FT levels were similar in both groups, FG correlated inversely with SHBG. In 19-39 yr women, FT levels were higher in "hirsute" subjects, SHBG values were similar in both groups, FG correlated positively with FT. Lowest SHBG values were observed at 15-18 years, but the slope of the decrease from 13-14 years values was greater in the "hirsute" group. FT values increased progressively with age, but the increase was greater in the "hirsute" group. Those results suggest an important role of SHBG decrease in adolescence vs. a more accentuated testosterone increase in adults, as factors conditioning the development of hirsutism in these two different periods of life.