Insulin-like growth factor-1 isoforms in human ovary. Preliminary report on the expression of the IGF-1 gene in PCOS patients and healthy controls.

Abstract

Insulin-like growth factor 1 (IGF-1), produced and secreted locally may affect the mechanisms of folliculogenesis and cause ovarian dysfunction, characteristic of PCOS. The expression of the IGF-1 gene gives rise to three different isoforms of the original molecule. Until now, the role of IGF-1 isoforms has been documented in the repair processes of damaged muscle fibers, cardomyocytes, hepatocytes, and neurons. The literature offers no reports on the presence and role of IGF-1 isoforms in the ovary The aim of the study was to assess the IGF-1A, B and C isoforms at the level of IGF-1 gene transcription in the ovaries of PCOS women and healthy controls. Serum samples and ovarian tissues from PCOS women, treated and non-treated with metformin (PCOS M(+); n = 12 and PCOS M(-), n = 37, respectively), and controls (n = 21) were obtained. The expression of mRNA species of IGF-1 in the ovaries was determined by quantitative RT-PCR. The presence of transcripts of three types of IGF-1 isoforms was observed in healthy controls and PCOS patients, regardless of metformin treatment. Total expression of all isoforms was higher in the M(-)(Me-26640) group as compared to the M(+)(Me- 13470) group, as well as controls (Me-17030)-(not significant, p = 0.061). Similar results for IGF-1A were obtained in all groups. The relative expression of IGF-1A was lower in the M(-)(86.02%) group and differed statistically from controls (91.38%) (p = 0.011). We detected the presence of mRNA for three IGF-1 isoforms in human ovary. To the best of our knowledge, this has been the first report on the presence of mRNA for three IGF-1 isoforms in human ovary. We found differences in the relative expression of IGF-1A isoforms between the investigated groups.