ABSTRACT
Objective To investigate the effect of triiodothyronine on the expression of alpha subunit of C protein Co (Coa) gene in cultured rat cerebral cortex neurons. Methods Primary cultured neurons of rat were prepared from the cerebral cortex at embryonic day 19. The neurons were cultured in DMEM supplemented with 15% fetal calf serum. After 7 days, the neurons were cultured in different media; DMEM supplemented with 15% fetal calf serum (group A), DMEM supplemented with 15% fetal calf serum stripped of thyroid hormone (group B), 0.5nmol/L T3-containing DMEM supplemented with 15% fetal calf serum stripped of thyroid hormone (group C) , 5nmol/L T3-containing DMEM supplemented with 15% fetal calf serum stripped of thyroid hormone (group D) and 50nmol/L T3-containing DMEM supplemented with 15% fetal calf serum stripped of thyroid hormone (group E). The neurons were cultured for another 7 days and total RNA was extracted. Goa mRNA leves were measured by competitive RT-PCR. Results As compared with group A, Coa mRNA leves in group B, D and E were low (P 0.05). Conclusion T, has dual effects on the expression of Coa gene in cultured rat cerebral cortex neurons. T3 down-regulated Coa mRNA in cultured neuron. However, in the absence of T3, Goa mRNA was also very low. Thyroid hormone may exert their action on brain development by regulating the the expression of Goa gene.