Expression of thyroid hormone receptors mRNAs in rat cerebral hemisphere neuronal cultures

• Published in: Brain research. Developmental brain research Vol. 69; no. 2; p. 173
• Main Authors: Puymirat, J, l'Hereault, S, Dussault, J H
• Format: Journal Article
• Language: English
• Published: Netherlands 23.10.1992
• Subjects: Animals; Blotting, Northern; Brain - embryology; Brain - physiology; Cells, Cultured; Fetus; Gene Expression; Gestational Age; Neurons - physiology; Poly A - genetics; Poly A - isolation & purification; Rats; Rats, Sprague-Dawley; Receptors, Thyroid Hormone - biosynthesis; Receptors, Thyroid Hormone - genetics; RNA - genetics; RNA - isolation & purification; RNA, Messenger - metabolism
• ISSN: 0165-3806
• DOI: 10.1016/0165-3806(92)90156-Q

We have studied the expression of the alpha and beta thyroid receptors mRNAs (TR-mRNAs) in cerebral hemisphere neuronal cultures, initiated from 15-day-old rat embryos, by northern analysis. In the cultures grown in the absence of L-triiodothyronine (L-T3), the alpha 2 TR-mRNAs were the predominant form of TR-mRNAs and were approximately 8 to 20-fold higher than the levels of the alpha 1 TR-mRNAs, depending on the age of the cultures. The levels of alpha 2 TR-mRNAs significantly increased by 1.8 fold between day 8 and 15 and remained on a plateau value thereafter until day 22. Over the same time period, there were no significant changes on the levels of alpha 1 TR-mRNAs. The ratio alpha 1/alpha 1 + alpha 2 TR-mRNAs decreased between day 8 and 15. The beta 1 TR-mRNAs increased by 8 fold between day 8 and day 22. On day 8, the beta 1 TR-mRNAs were 1.8 fold lower than the levels of the alpha 1 TR-mRNAs while they were 6 fold higher on day 22. L-T3 treatment of the cultures had no effect on the levels of the alpha 1, alpha 2 and beta 1 TR-mRNAs. The differential temporal expression of the alpha 1 and beta 1 TR-mRNAs suggests distinct functions for both types of T3 receptors in neuronal maturation.