Immunocytochemical evidence for the presence and location of the neurotrophin–Trk receptor family in adult human preovulatory ovarian follicles

Objective This study was undertaken to evaluate the presence or absence of neurotrophins and their respective receptors within adult human preovulatory follicles. Study design Prospective study of neurotrophins and their receptors in follicular cells and unfertilized oocytes from women undergoing aspiration for in vitro fertilization/intracytoplasmic sperm injection. Cells (mural and cumulus granulosa cells, unfertilized oocytes) were examined for immunocytochemical staining of neurotrophin and receptor proteins. Results Mural and cumulus granulosa cells were positive for BDNF, NT-4/5, NT-3, and NGF, as well as for Trk B, Trk C, and Trk A receptors. Unfertilized oocytes were positive for Trk B, Trk C, and Trk A receptors. Conclusion Neurotrophins and their respective receptor proteins are present within the mural and cumulus granulosa cells of adult human preovulatory follicles. Neurotrophin receptors are present in human unfertilized oocytes. The location of the neurotrophins and their receptors suggest both an autocrine and paracrine function within the adult human ovarian follicle.