Such models include Trh −/− mice which exhibit central hypothyroidism with elevated TSH and hyperglycaemia and glycoprotein α subunit (Cga/Gsu) −/− null mice in whom TSH, T4, FSH and LH are undetectable (Yamada et al. 1997, Stahl et al. 1999). The gene discussed is ART4; the disease is Central hypothyroidism.