Antagonism of Adrenocortical Extract and Cortisone to Desoxycorticos-terone: Brain Excitability in Adrenalectomized Rats.

Abstract

The electroshock seizure thresholds (EST) of intact and adrenalectomized rats implanted with desoxycorticosterone acetate (DCA) and given water or a 0.9% NaCl soln. to drink have been measured. The rate of elevation of EST was as follows, in increasing order: intact controls on water; intact DCA-implanted animals on water; adrenalectomized DCA-implanted rats on water; adrenalectomized DCA-implanted rats on 0.9% NaCl soln. Cortisone and adreno-cortical extract (ACE) lowered the elevated EST of adrenalectomized DCA-implanted rats, which were given a soln. of NaCl to drink, by 8.5% in 6 days. Following withdrawal of cortisone or ACE the EST returned to pretreatment levels in 11 days. Cortisone lowered the elevated EST of adrenalectomized DCA-implanted rats, given water to drink, by 10% in 3 days; following withdrawal of cortisone the EST returned to the pretreatment level in 2 days. It has been suggested that the results obtained provide evidence for the concept that cortisone and DCA compete for strategic loci in target cells.