Modifications of striatal dopamine levels by steroid contraceptive drugs in mice and rats.

The effect of steroid contraceptive drugs (SCDs) on the concentration of dopamine (DA) in the striatum was studied in mice and rats. Mestranol was combined with each one of the three progestins, lynestrenol, norethindrone and norethynodrel. Treatments were given daily for 1, 4 or 30 days; animals were sacrificed 1 or 18 h after the last administration. In all groups, with the exception of the animals sacrificed 1 h after an acute treatment, striatal DA was significantly lower than in controls.