Influences of estrogen and/or progesterone on some dopamine related behavior in rats

1. The effects of ovariectomy and/or of female hormonal treatments on open-field behavior, apomorphine-induced stereotypies and haloperidol-induced catalepsy were studied in rats. 2. Rat's locomotion frequency was significantly decreased by 17 beta-estradiol and estradiol plus progesterone treatments; this open-field parameter was not affected by progesterone administration per se. 3. 17 beta-estradiol and progesterone treatments, alone or in combination decreased apomorphine-stereotyped behavior. 4. Haloperidol effects were higher in both 17 beta-estradiol and 17 beta-estradiol plus progesterone treated rats. 5. Progesterone treatment alone, decreased the duration of catalepsy induced by the minor (1.0 mg/kg) neuroleptic dose. 6. These results were discussed in the light of a possible interference of estrogen and/or progesterone on dopaminergic transmission at the level of the nigroestratial pathway.