Chronic estradiol treatment increases anterior pituitary but not striatal D2 dopamine receptor mRNA levels in rats.
The effect of chronic 17 beta-estradiol treatment (10 micrograms, twice each day, for 2 weeks) of ovariectomized rats on D2 dopamine (DA) receptor mRNA levels was investigated in striatum and anterior pituitary gland tissues. We used 32P-labeled probes specific for D2 receptor and beta-actin mRNAs in Northern blot analysis. The ratio of D2 DA receptor mRNA/beta-actin mRNA level was significantly increased in the anterior pituitary of estradiol-treated rats compared to vehicle-treated animals. The D2 DA receptor mRNA/beta-actin mRNA ratio in the striatum was not affected by estradiol treatment. However, the medial portion of the striatum showed a significantly lower ratio compared to the lateral portion of the striatum in both vehicle- and estradiol-treated rats. Thus, the estradiol effect on anterior pituitary D2 receptors may implicate transcriptional regulation, whereas our results do not support this hypothesis for the estradiol action on striatal D2 receptors.
Lévesque
D
D
Department of Molecular Endocrinology, Laval University, Ste-Foy, Que., Canada.
Gagné
B
B
Barden
N
N
Di Paolo
T
T
D000199:Actins / Q000235:genetics; D000818:Animals; D001345:Autoradiography; D015152:Blotting, Northern; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D009928:Organ Specificity; D010052:Ovariectomy; D010761:Phosphorus Radioisotopes; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000502:physiology*; D015347:RNA Probes; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000235:genetics*
D000199:Actins; D010761:Phosphorus Radioisotopes; D015347:RNA Probes; D012333:RNA, Messenger; D017448:Receptors, Dopamine D2; D004958:Estradiol