The contributions of oestrogen and growth factors to increased adrenal androgen secretion in polycystic ovary syndrome

Adrenal hyperandrogenism is prevalent in many women with polycystic ovary s yndrome (PCOS), although the expression of this enhanced secretion may be h eterogeneous. Since no single factor acts in isolation, this study was perf ormed to assess the influence of oestradiol (total and unbound), insulin, i nsulin-like growth factor (IGF)-I, IGF-II and the binding proteins IGFBP-I, and IGFBP-3, on basal and adrenocorticotrophic hormone (ACTH) stimulated a drenal androgen secretion in 25 women with PCOS and 10 matched ovulatory co ntrols. Women with PCOS exhibited elevations of all androgens as well as un bound oestradiol, insulin and non-IGFBP-1 bound IGF-I. Positive correlation s were noted between oestrogen and basal and ACTH stimulated Delta(5) adren al androgens. Serum IGF-I was only correlated with basal dehydroepiandroste rone sulphate (DHEA-S), while insulin exhibited a strong correlation with t he Delta(4) pathway and androstenedione formation in particular. This corre lation was also confirmed by dividing the PCOS group into those women with and without hyperinsulinaemia. The activity of 17,20 lyase favouring andros tenedione was increased in the hyperinsulinaemic women. By multivariate ana lyses, body mass index did not influence these findings. Although there are inherent difficulties in making major conclusions based on correlative ana lyses, it is suggested that oestrogen may have a greater influence on enhan cing Delta(5) adrenal androgen secretion, and insulin a greater effect on t he Delta(4) pathway. In turn, the relative importance of these influences m ay contribute to the heterogeneous nature of adrenal hyperandrogenism in PC OS.