The endocrine system, vertigo and balance.

Steroid, amine and peptide hormones affect the peripheral vestibular system. Vasopressin hypersensitivity of the endolymphatic sac may be implicated in the pathogenesis of Meniere's disease. Specific vasopressin antagonists will help define the role of vasopressin in Meniere's disease. The modulation of central vestibular pathways by neuroactive steroids may involve effects on gamma-aminobutyric acid-ergic and glutaminergic pathways. The vestibular nuclei also express enzymes that are important in the synthesis of steroids and the modulation of their activity. Steroids mediate both facilitatory and deleterious effects of stress on vestibular compensation. The quality and quantity of stressor that determines the pattern of hormonal output, may be important. Clinical observation suggests that episodic ataxia type 2, a P/Q calcium channelopathy, may be phenotypically modulated by endocrine fluctuations. Steroid hormones may affect the episodic ataxia type 2 phenotype by modulation of voltage-gated calcium channel activity via second messenger systems and ion channel subunit expression. Despite evidence to support the link, the role of the endocrine system in vestibular function and disease is as yet virtually unexplored.