Identification of new proteins in follicular fluid of mature human follicles.

Proteins present in human follicular fluid (HFF) have been poorly characterized to date. The purpose of our study was to analyse the protein content and identify new proteins originating from fluid of mature human follicles. A total of six females from infertile couples referred for in vitro fertilization (IVF) were stimulated and 44 follicular fluid samples from mature follicles yielding an oocyte were collected 34-36 h after human chorionic gonadotropin administration. HFF samples were processed for high-resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Comparative analysis of the 2-D gels revealed up to 600 spots, of which four were selected because of variations in their expression level. Using direct sequencing procedures (Edman degradation) or matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS), these four spots were identified as three new proteins: thioredoxin peroxydase 1 (TDPX1), transthyretin (TTR) and retinol-binding protein (RBP). The proteins identified here may emerge as potential candidates for specific functions during folliculogenesis and may prove useful as biomedical markers for follicle and/or oocyte maturation.