Insulin-like growth factors and insulin-like growth factor binding proteins in androgen-dominant ovarian follicles from testosterone-treated female-to-male trans-sexuals.

OBJECTIVE

To determine insulin-like growth factor (IGF)-I and IGF-II levels, IGF binding protein (IGFBP) profile, and IGFBP-4 protease activity in androgen-dominant follicular fluid (FF) from female-to-male trans-sexuals and to compare with those in follicles from normocycling women.

DESIGN

Follicular fluid samples were obtained from four female-to-male trans-sexuals and 15 women with normo-ovulatory cycles at the Dijkzigt Academic Hospital. Western ligand blot analysis and protease assays were used to determine IGFBP profile, and immunoradiometric assays were used to detect IGF levels.

SETTING

The study was performed in two academic medical centers.

PATIENT(S): Female-to-male trans-sexuals and women with normo-ovulatory cycles.

INTERVENTIONS: None.

MAIN OUTCOME MEASURE(S): Determination of IGF levels and IGFBP profile.

RESULT(S): Insulin-like growth factor I levels in FF from female-to-male trans-sexuals were not significantly different compared with levels in androgen-dominant FF and estrogen-dominant FF. Significantly lower levels of IGF-II were observed in FF from female-to-male trans-sexuals than in estrogen-dominant FF, whereas IGF-II levels in FF from female-to-male trans-sexuals were not significantly different than those in androgen-dominant FF. Similar IGFBP profiles from FF from female-to-male trans-sexuals and androgen-dominant FF were noted, with markedly elevated levels of the 31- and 24-kd IGFBPs and a 28-kd IGFBP, compared with estrogen-dominant FF. An IGFBP-4-specific metalloserine protease that is active in estrogen-dominant FF likewise was undetected in FF from female-to-male trans-sexuals.

CONCLUSION(S): Follicles developing under the influence of exogenous androgens in ovaries in female-to-male trans-sexuals appear to be similar to androgen-dominant follicles in normo-ovulatory women with regard to IGF-I and IGF-II levels, IGFBP profile, and the absence of IGFBP-4 protease activity.