[3H]Dexamethasone binding in rat frontal cortex.

The work described in this paper presents evidence for the existence of specific glucocorticoid receptors in the rat frontal cortex. Using [3H]dexamethasone we found a Kd approximately 6 nM and a Bmax approximately 270 fmol/mg protein, concentrations that were about 75% of those found in hippocampus. [3H]dexamethasone binding in the frontal cortex, like that in hippocampus, was regulated by the corticosterone: thus, one-week treatment with corticosterone results in a decrease and long-term adrenalectomy results in an increase in [3H]dexamethasone binding. Developmentally, as reported for other brain regions, [3H]dexamethasone binding in frontal cortex was low during the first week of life and then rose during the following 10 days to approximate adult levels. These results are discussed in terms of providing a possible mechanism for the influence of corticoids on catecholamine activity in the frontal cortex.