[Hormonal Control of the Inner Ear. Fiction or Reality?]

The aetiology of numerous functional disorders of the inner ear is still unknown. In particular, it is unclear whether these hearing disorders are a result of a primary damage to the sensory or secretory epithelium, or perhaps a result of a disturbed cochlear control mechanism. In the kidney, ion transport is controlled by hormonal influence mediated by an adenylate cyclase mechanism. Adenylate cyclase has been localized biochemically and cytochemically in the inner ear. Its activity can be increased with vasopressin and parathormone. Thus the question has been raised whether cellular metabolism and transport in the inner ear is indeed controlled by hormonal influence. The results of the electronmicroscopic-cytochemical localization studies of adenylate cyclase in the lateral wall of the cochlea and in the endolymphatic sac are presented, and their possible physiological significance is discussed.