Characterization of the striatal dopamine receptor supersensitivity produced by estrogen treatment of male rats

Estrogen treatment of male rats produced an increase in the number of striatal dopamine receptors, without altering their affinity. This effect only occurs in vivo and has a slow onset. Only the β-diastereomer of 17-estradiol was active. Other striatal receptors appeared to be unchanged as was the presynaptic uptake of dopamine. Hypophysectomy completely blocked the response to estrogen as measured on striatal dopamine receptors and on stereotypy, a behavior associated with striatal dopamine receptor stimulation. These results are relevant to the clinical observations of chorea associated with the use of oral contraceptives or with pregnancy.