Effect of chronic cold exposure on tyrosine hydroxylase mRNA in rat adrenal gland

The effect of chronic stress on the levels of tyrosine hydroxylase (TH) RNA in rat adrenal gland was investigated by RNA-DNA hybridization using a cloned TH cDNA probe. Results of dot-blot hybridization experiments and northern analysis demonstrate that exposure of animals to cold for 1 week results in a 4-5-fold increase in the relative abundance of TH mRNA. This increase in TH mRNA level may underlie the increase in adrenal TH activity that is known to occur when rats are exposed to such cold stress.