Angiotensin II receptors are upregulated by estradiol and progesterone in the locus coeruleus, median preoptic nucleus and subfornical organ of ovariectomized rats.
Angiotensin II (Ang II) receptors in specific brain areas and in the anterior pituitary are controlled by reproductive hormones. Since Ang II also plays a role in controlling reproductive functions, such as luteinizing hormone and prolactin secretion, the objective of the present study was to evaluate the regulation of Ang II receptors by estradiol (E(2)) and progesterone (P) in areas of the brain involved in homeostatic and reproductive functions, such as the locus coeruleus (LC), median preoptic nucleus (MnPO) and subfornical organ (SFO). Adult female rats were ovariectomized under anesthesia and divided into 2 groups after 2 weeks: OVX plus E(2)/P replacement (OVXE(2)P) and OVX plus oil vehicle (OVX). E(2) was injected for 3 consecutive days followed by an injection of P on the 4th day. Animals were killed by decapitation and the brains were removed and frozen. Consecutive coronal brain sections were cut in a cryostat and Ang II receptors were quantified by autoradiography in the MnPO, LC and SFO. Treatment of OVX rats with E(2) and P induced a significant increase in the Ang II receptor binding (fmol/mg protein) in the MnPO (OVX: 4.48 +/- 0.58 and OVXE(2)P: 9.89 +/- 1.65), LC (OVX: 2.72 +/- 0.37 and OVXE(2)P: 8.03 +/- 0.9) and SFO (OVX: 5.45 +/- 0.66 and OVXE(2)P: 10.73 +/- 1.79) compared to OVX animals treated with the vehicle, P < 0.05. In conclusion, these results show that Ang II receptors are upregulated by E(2) and P in the LC, MnPO and SFO of ovariectomized rats.
Donadio
Márcio Vinícius Fagundes
MV
Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, ICBS, Universidade Federal do Rio Grande do Sul, UFRGS, Sarmento Leite 500, Porto Alegre, RS 90050-170, Brazil.
Gomes
Cármen Marilei
CM
Sagae
Sara Cristina
SC
Franci
Celso Rodrigues
CR
Anselmo-Franci
Janete A
JA
Lucion
Aldo Bolten
AB
Sanvitto
Gilberto Luiz
GL
D000758:Anesthesia; D000818:Animals; D001345:Autoradiography; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008125:Locus Coeruleus / Q000187:drug effects / Q000378:metabolism*; D010052:Ovariectomy; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000187:drug effects*; D013356:Subfornical Organ / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
D011945:Receptors, Angiotensin; C405353:sarcosine(1)-angiotensin II receptor; D011374:Progesterone; D004958:Estradiol