Endocrinology: Follicular fluid insulin-like growth factor-I and insulin-like growth factor-II concentrations vary as a function of day 3 serum follicle stimulating hormone

We determined follicular fluid concentrations of insulin-likegrowth factor (IGF)-I, IGF-II and inhibin as a function of day3 serum follicle stimulating hormone (FSH) in 16 women undergoingfollicular fluid aspiration in preparation for in-vitro fertilizationand embryo transfer. Follicular fluid concentrations of IGF-Iand IGF-II were significantly less in the ‘low’FSH group as compared to the ‘high’ FSH group. Themean IGF-I concentration was 67.6 ng/ml [confidence intervals(CI) 51.6–92.5] in the ‘low’ FSH group comparedto 87.1 ng/ml (CI 72.8–104.2; P < 0.025) in the ‘high’FSH group. Mean IGF-II concentrations were 354.8 ng/ml (CI 297.8–422.9)in the ‘low’ FSH group compared to 489.8 ng/ml (CI384.6–624.5; P < 0.05) in the ‘high’ FSHgroup. Follicular fluid inhibin concentrations did not differbetween groups. These differences in follicular fluid IGF asa function of day 3 FSH may raise questions regarding the rolegrowth factors play in the physiological processes of the ageingfollicle.