Expression of insulin-like growth factor (IGF), IGF receptor, and IGF-binding protein messenger ribonucleic acids in luteinized granulosa cells from different size follicles after controlled ovarian hyperstimulation

Purpose: This study was conducted to determine the gene expression of insulin-like growth factors (IGFs), their receptors, and binding proteins (IGFBPs) in human luteinized granulosa cells collected during ovum retrieval. Methods: cDNA probes were used to analyze the gene expression of IGF-I, IGF-II, IGF type 1 receptor (IGFR-1), IGF type 2 receptor (IGFR-2), and IGFBP-1 to -6 in luteinized granulosa cells. Results: The levels of IGFBP-5 transcripts of the luteinized granulosa cells increased with increasing follicular fluid (FF) volume when follicles were grouped into 3 volume categories of ≤1.5 mL; >1.5 mL but ≤4.5 mL; and >4.5 mL (0.28 ± 0.64 vs. 0.41 ± 0.76 vs. 0.46 ± 0.92, p = 0.037). Conclusions: The increased levels of IGFBP-5 transcripts in luteinized granulosa cells found with increased follicular fluid volume after COH may favor a shift toward diminished action of IGFs in larger follicles immediately prior to ovulation.