Responsiveness of α1, and β1Cochlear Na, K-ATPase Isoforms to Thyroid Hormone

Publisher Website
Google Scholar
Abstract
The effects of thyroid hormone on Na, K-ATPase subunit isoforms under euthyroid (EUTH), hypothyroid (HYPO) and hyperthyroid (HYPER) states were investigated via immunocytochemistry and the use of polyclonal antibodies specific to each isoform (α1 α2, α3 and β1, β2). in HYPO animals, there was a distinct decrease in Na, K-ATPase α1, isoform immunoreactivity in the stria vascularis (SV), spiral ganglion (SG) cells, spiral limbus (SLi) and cochlear nerve (CN) as compared with that in EUTH animals by the 17th day of the experiment. Immunostaining of the α1, isoform increased in HYPER animals as compared with that in HYPO animals, and reached a level comparable to that in EUTH animals after 2 days of triiodothyronine (T3) treatment. Levels of α2 α3 and β2 isoforms did not appear to be affected by T3 administration. by the 19th day of a low I2 diet, the immunoreactive intensity of the β1, isoform was reduced in cochlear tissues of HYPO animals as compared with that in EUTH animals. the immunoreactivity of the β1, isoform increased after treatment with T, for 4 days and was comparable with levels in EUTH animals. These data indicate that α1, and β1, isoforms within specific cochlear regions of the adult rat are responsive to thyroid hormone.