title: Elevation of striatal dopamine receptors by estrogen: dose and time studies.
abstract: Administration to male rats of a single dose of 17 beta-estradiol valerate (8-500 micrograms/rat) or implantation of a pellet containing 17 beta-estradiol (0.5-50 mg/rat) increased serum 17 beta-estradiol levels in a dose-dependent relationship when measured on the sixth day after administration. At the same time, after these doses, the serum rat prolactin (rPRL) levels were doubled and the striatal 3,4-dihydroxyphenylethylamine (DA, dopamine) receptor densities were increased 20%. A single dose of 17 beta-estradiol valerate of 4 micrograms/rat or less did not alter serum 17 beta-estradiol or rPRL levels or the striatal DA receptor density. After the single injection of 17 beta-estradiol valerate (125 micrograms/rat) the serum 17 beta-estradiol levels peaked at 1 day, the serum rPRL levels peaked at 2 days, and the striatal DA receptor density elevation peaked from 4 to 8 days. Implantation of a pellet containing 17 beta-estradiol (25 mg/rat) produced a constant elevation of serum 17 beta-estradiol levels from 1 to 10 days. Whereas the serum rPRL levels were continuously elevated about two-fold, the densities of the striatal DA receptors were increased significantly by 20-25% only from 4 to 8 days after pellet implantation. These results indicate that striatal DA receptor density rises and returns to control levels during the constant elevation of serum 17 beta-estradiol and rPRL levels.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000032:analysis* / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D005260:Female; D008297:Male; D011388:Prolactin / Q000097:blood; D051381:Rats; D011954:Receptors, Dopamine / Q000032:analysis / Q000187:drug effects*; D013997:Time Factors
chemical_list: D011954:Receptors, Dopamine; D004958:Estradiol; D011388:Prolactin