title: Tyrosine kinase B receptor and its activated neurotrophins in ovaries from human fetuses and adults.
abstract: The signals initiating the growth of primordial follicles are unknown. Growth factors such as neurotrophin 4/5 (NT-4/5) and brain-derived neurotrophic factor (BDNF) may play a role in this process. To investigate the expression of NT-4/5 and BDNF and their receptor tyrosine kinase B (TrkB) in the early developing follicles, we fixed and froze 12 ovarian samples from adolescents/adults and 31 ovaries from human fetuses. The fixed samples were prepared for immunohistochemical staining for NT-4/5, BDNF and the TrkB receptor. Total RNA was extracted from the frozen ovarian samples, and the expression of NT-4/5, BDNF and the TrkB receptor (full length and two truncated isoforms) was investigated by RT-PCR. Products were resolved by 1% agarose gel electrophoresis and image analysis. Immunohistochemical staining revealed the expression of NT-4/5 and BDNF mainly in oocytes and, in a minority of samples, also in the granulosa cells (GCs); TrkB receptor was identified in oocytes and GCs. Transcripts of NT-4/5, BDNF and all forms of TrkB receptor were identified in the samples. To elucidate whether indeed NT-4/5 and BDNF are involved in growth initiation of human primordial follicles, they should be added to the culture medium.
authors.affiliation: Infertility and IVF UnitHelen Schneider's Women Hospital, Rabin Medical Center, Petach Tikva and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Harel
authors.forename: S
authors.initials: S
authors.lastname: Jin
authors.forename: B
authors.initials: B
authors.lastname: Fisch
authors.forename: D
authors.initials: D
authors.lastname: Feldberg
authors.forename: H
authors.initials: H
authors.lastname: Krissi
authors.forename: C
authors.initials: C
authors.lastname: Felz
authors.forename: S
authors.initials: S
authors.lastname: Freimann
authors.forename: S L
authors.initials: SL
authors.lastname: Tan
authors.forename: A
authors.initials: A
authors.lastname: Ao
authors.forename: R
authors.initials: R
authors.lastname: Abir
mesh_terms: D000293:Adolescent; D000328:Adult; D019208:Brain-Derived Neurotrophic Factor / Q000032:analysis / Q000235:genetics; D005260:Female; D005333:Fetus; D006801:Humans; D007150:Immunohistochemistry; D009414:Nerve Growth Factors / Q000032:analysis* / Q000235:genetics; D006080:Ovarian Follicle / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D010053:Ovary / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020813:Receptor, trkB / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D012333:RNA, Messenger; C071951:neurotrophin 5; D020813:Receptor, trkB; C073922:neurotrophin 4