Role of the renin-angiotensin system in cardiac hypertrophy induced in rats by hyperthyroidism

Hiroyuki Kobori, Atsuhiro Ichihara, Hiromichi Suzuki, Tsuneo Takenaka, Yutaka Miyashita, Matsuhiko Hayashi, Takao Saruta

Research output: Contribution to journalArticle

Abstract

This study was conducted to examine whether the renin-angiotensin system contributes to hyperthyroidism-induced cardiac hypertrophy without involving the sympathetic nervous system. Sprague-Dawley rats were divided into control-innervated, control-denervated, hyperthyroid-innervated, and hyper thyroid-denervated groups using intra-peritoneal injections of thyroxine and 6-hydroxydopamine. After 8 wk, the heart-to-body weight ratio increased in hyperthyroid groups (63%), and this increase was only partially inhibited by sympathetic denervation. Radioimmunoassays and reverse transcription- polymerase chain reaction revealed increased cardiac levels of renin (33%) and angiotensin II (53%) and enhanced cardiac expression of renin mRNA (225%) in the hyperthyroid groups. These increases were unaffected by sympathetic denervation or 24-h bilateral nephrectomy. In addition, losartan and nicardipine decreased systolic blood pressure to the same extent, but only losartan caused regression of thyroxine-induced cardiac hypertrophy. These results suggest that thyroid hormone activates the cardiac renin-angiotensin system without involving the sympathetic nervous system or the circulating renin-angiotensin system; the activated renin-angiotensin system contributes to cardiac hypertrophy in hyperthyroidism.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume273
Issue number2 42-2
Publication statusPublished - 1997

Fingerprint

Cardiomegaly
Hyperthyroidism
Renin-Angiotensin System
Sympathectomy
Losartan
Sympathetic Nervous System
Thyroxine
Renin
Blood Pressure
Nicardipine
Oxidopamine
Nephrectomy
Thyroid Hormones
Angiotensin II
Reverse Transcription
Radioimmunoassay
Sprague Dawley Rats
Thyroid Gland
Body Weight
Polymerase Chain Reaction

Keywords

  • Angiotensin II type 1 receptor antagonist
  • Chemical sympathectomy
  • Polymerase chain reaction
  • Tissue renin

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Kobori, H., Ichihara, A., Suzuki, H., Takenaka, T., Miyashita, Y., Hayashi, M., & Saruta, T. (1997). Role of the renin-angiotensin system in cardiac hypertrophy induced in rats by hyperthyroidism. American Journal of Physiology - Heart and Circulatory Physiology, 273(2 42-2).

Role of the renin-angiotensin system in cardiac hypertrophy induced in rats by hyperthyroidism. / Kobori, Hiroyuki; Ichihara, Atsuhiro; Suzuki, Hiromichi; Takenaka, Tsuneo; Miyashita, Yutaka; Hayashi, Matsuhiko; Saruta, Takao.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 273, No. 2 42-2, 1997.

Research output: Contribution to journalArticle

Kobori, H, Ichihara, A, Suzuki, H, Takenaka, T, Miyashita, Y, Hayashi, M & Saruta, T 1997, 'Role of the renin-angiotensin system in cardiac hypertrophy induced in rats by hyperthyroidism', American Journal of Physiology - Heart and Circulatory Physiology, vol. 273, no. 2 42-2.
Kobori, Hiroyuki ; Ichihara, Atsuhiro ; Suzuki, Hiromichi ; Takenaka, Tsuneo ; Miyashita, Yutaka ; Hayashi, Matsuhiko ; Saruta, Takao. / Role of the renin-angiotensin system in cardiac hypertrophy induced in rats by hyperthyroidism. In: American Journal of Physiology - Heart and Circulatory Physiology. 1997 ; Vol. 273, No. 2 42-2.
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