Background : The thyroid gland and its hormones participate and have a critical part in the development and function of different parts of the body like the kidney, which is the most important site of renin synthesis and release which is followed by angiotensin and aldosterone formation. As needs are; any abnormality in this gland’s function can harm the Renin-Angiotensin -Aldosterone System.
We aimed to discover the effects of using an Angiotensin Receptor Blocker (Olmesartan) on the Renin-Angiotensin-Aldosterone System (RAAS) in rats with abnormal thyroid functions.
Methods : Thirty rats were used and three groups were formed. 6 rats (First group) were the control. 12 rats (Second group) was the hypothyroid group (6 rats control, 6 rats given Olmesartan). 12 rats (the Third group) was the hyperthyroid group (6 rats control, 6 rats given Olmesartan).
L-Thyroxine and Propylthiouracil (PTU) were given orally daily for induction of hyperthyroidism and hypothyroidism respectively.
Blood pressure measurement was done on days 1 and 40th day of the study. The rats were sacrificed on day 40th of the study.
Results : In hyperthyroid rats, T4 was raised and the use of Olmesartan on these rats caused a lowering of this parameter. Renin levels increased in hyperthyroid rats treated with Olmesartan. Angiotensin I increased in hyperthyroid rats. Systolic BP increased in hyperthyroid rats and the use of Olmesartan on these rats caused a lowering of this parameter. Diastolic BP and Mean BP both increased in the hyperthyroid rats.
T3 and T4 levels dropped and TSH increased in hypothyroid and hypothyroid treated with Olmesartan rats. The level of Renin decreased in hypothyroid rats and increased in Olmesartan-treated rats. Angiotensin I decreased in hypothyroid and Olmesartan-treated hypothyroid rats. Blood Pressure components decreased in both hypothyroid and hypothyroid treated with Olmesartan rats.
Conclusions : Olmesartan was able to decrease T4 level along with Systolic BP in hyperthyroid rats. It also decreased Angiotensin I and Blood Pressure components in hypothyroid rats.