Modulatory effects of progesterone upon dopamine release from the corpus striatum of ovariectomized estrogen-treated rats are stereo-specific.

We have shown previously that progesterone linked with bovine serum albumin at position 3 of the progesterone molecule (P-3-BSA) was effective in modulating (both stimulating and inhibiting) amphetamine (AMPH)-evoked dopamine (DA) release in vitro from superfused corpus striatal (CS) tissue fragments of ovariectomized estrogen-primed rats. To examine the stereospecificity of this effect, progesterone linked with bovine serum albumin at position 11 (P-11-BSA) and deoxycorticosterone linked with bovine serum albumin at position 21 (DOC-BSA) were tested for their ability to modulate amphetamine-stimulated DA release in vitro when administered in either a pulsatile or a continuous infusion mode at different doses. The results demonstrate that a specific orientation of the P-BSA molecule is required for differential modulation of AMPH stimulated DA release from the CS of ovariectomized estrogen-treated rats, since DOC-BSA was ineffective and P-11-BSA showed only a stimulatory effect.