The balance between oligodendrocyte and astrocyte production in major white matter tracts is linearly related to serum total thyroxine.
Sharlin DS, Tighe D, Gilbert ME, Zoeller RT. The balance between oligodendrocyte and astrocyte production in major white matter tracts is linearly related to serum total thyroxine. Endocrinology. 2008 May; 149(5):2527-36.