Induction of cell proliferation in avian inner ear sensory epithelia by insulin-like growth factor-I and insulin

✍ Scribed by Oesterle, Elizabeth C.; Tsue, Terance T.; Rubel, Edwin W

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 210 KB
• Volume: 380
• Category: Article
• ISSN: 0021-9967
• DOI: 10.1002/(sici)1096-9861(19970407)380:2<262::aid-cne8>3.0.co;2-1

✦ Synopsis

Postembryonic production of inner-ear hair cells occurs both normally and after insult in lower vertebrates and avians. To determine how this proliferation is controlled, several growth factors were tested for effects on progenitor-cell division in cultured avian vestibular sensory epithelium. Mitogenic effects of bombesin, epidermal growth factor, insulin-like growth factor-I (IGF-I), insulin, and transforming growth factor-alpha were assayed in organo-typic cultures of utricles from the mature, undamaged (normal) chicken inner ear. Tritiated thymidine and autoradiographic techniques and 5-bromo-2'-deoxyuridine (BrdU) immunocytochemistry were used to identify cells synthesizing DNA. IGF-I stimulated DNA synthesis in the vestibular sensory receptor epithelium in a dose-dependent manner. DNA synthesis was also stimulated by insulin. These results suggest that stimulation of the IGF-I receptors by IGF-I or insulin binding stimulates cell proliferation in the mature avian vestibular sensory epithelium.