Increased Cardiac Angiotensin II Receptors in Angiotensinogen-Deficient Mice
| Autor: | Machiko Yabana, Masao Ishii, Shunichi Kobayashi, Kazuo Murakami, Satoshi Umemura, Nobuo Nyui, Hitoshi Miyazaki, Akiyoshi Fukamizu, Tomoaki Ishigami, Kouichi Tamura, Minoru Kihara, Hisao Ochiai, Yoichi Sumida |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
medicine.medical_specialty
Angiotensin receptor Prohormone Angiotensinogen Peptide hormone Biology Mice Radioligand Assay Organ Culture Techniques Downregulation and upregulation In vivo Internal medicine Renin–angiotensin system Internal Medicine medicine Animals Receptor Mice Knockout Receptors Angiotensin Angiotensin II Myocardium Blotting Northern Endocrinology Hypotension medicine.drug |
| Zdroj: | Hypertension. 31:45-49 |
| ISSN: | 1524-4563 0194-911X |
| Popis: | Abstract —Two subtypes of angiotensin II (Ang II) receptors, type 1 (AT 1 -R) and type 2 (AT 2 -R), have been identified in the heart. However, little is known about the regulation of cardiac AT 1 -R and AT 2 -R by Ang II in vivo. Thus, we examined cardiac AT 1 -R and AT 2 -R in angiotensinogen-deficient ( Atg-/- ) mice that are hypotensive and lack circulating Ang II. Cardiac Ang II receptors (Ang II-R) were assessed by radioligand binding with 125 I-[Sar 1 ,Ile 8 ]–Ang II in plasma membrane fractions. AT 1 -R and AT 2 -R were distinguished using their specific antagonists CV-11974 and PD123319 , respectively. Total densities of Ang II-R and AT 1 -R density were significantly greater in the Atg-/- mice than Atg+/+ mice (31.1±2.8 versus18.8±2.1, 28.7±3.0 versus16.9±2.3 fmol/mg protein, P 2 -R showed a slight but not significant increase in Atg-/- mice relative to Atg+/+ control animals. K d values were not different between the two groups. In contrast to binding experiments, levels of Ang II type 1a receptor (AT 1a -R) and AT 2 -R mRNA did not differ between Atg-/- and Atg+/+ mice. These results suggest that lack of Ang II may upregulate AT 1 -R through translational and/or posttranslational mechanisms in Atg-/- mice. |
| Databáze: | OpenAIRE |
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