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 transsexuals than in estrogen-dominant FF, whereas IGF-II levels in FF from female-to-male transsexuals 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 normoovulatory women with regard to IGF-I and IGF-II levels, IGFBP profile, and the absence of IGFBP-4 protease activity.

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