Transcriptional and posttranscriptional regulation of Na+,K+-ATPase α isoforms by thyroid hormone in the developing rat brain

TRANSCRIPTIONAL and post-transcriptional events involved in the induction of sodium potassium adenosine triphosphatase (Na+,K+-ATPase) by thyroid hormone (T-3) were investigated. In vitro transcription of nuclei isolated from cerebra of 5- and 15-day-old normal and hypothyroid rats showed that transcription of all a mRNA isoforms (alpha(1), alpha(2) and alpha(3)) of Na+,K+-ATPase are sensitive to T-3. This is evidenced by a 50-70% reduction in the rates of transcription of alpha(1) and alpha(3) mRNA and 20-40% reduction of alpha(2) mRNA in nuclei from hypothyroid cerebra compared with those from normal controls. Preincubation of nuclei from hypothyroid cerebra with T-3 prior to transcription also showed an increase in the rates of transcription of these mRNAs. At the post-transcriptional level, T-3 enhanced the half life of alpha(3) mRNA by 1.5-fold with no discernible effect on alpha(1) and alpha(2) mRNA. NeuroReport 10:2325-2328 (C) 1999 Lippincott Williams & Wilkins.