TRIIODOTHYRONINE REGULATES SOMATOSTATIN GENE-EXPRESSION IN CULTURED FETAL-RAT CEREBROCORTICAL CELLS

The effect of triiodothyronine (T-3) on somatostatin (SS) mRNA levels in cultured fetal rat cerebrocortical cells was studied. Two different experimental approaches were sought. They differed in the length of t ime in which cells were deprived of thyroid hormones prior to the addi tion of exogenous T-3. When the cells were not deprived of thyroid hor mones, T-3 caused a dose-related decrease in SS mRNA content at all do ses tested. However, when the cells were deprived of T-3 for 24 h, a b iphasic effect was observed. These findings suggest that T-3 regulates SS gene expression in fetal cultured cerebrocortical cells.