Choosing among renin-angiotensin system blockers for the management of hypertension: from pharmacology to clinical efficacy

Comparison of effects of telmisartan versus valsartan on post-induction hypotension during noncardiac surgery: a prospective observational study

BACKGROUND

Telmisartan is considered more potent than valsartan. Hemodynamic response during anesthesia induction may be influenced by anti-hypertension (HTN) medication. The present study compared the effect of anti-HTN medications on post-induction hypotension during noncardiac surgeries.

METHODS

This observational study standardized the anesthetic regimen across patients, with hypotension defined as mean blood pressure (BP) of less than 65 mmHg. The hemodynamic changes within 5 min before and after endotracheal intubation, and within 10 min before and after surgical incision were measured. Transthoracic echocardiographic evaluation of the left ventricle (LV) during anesthesia induction was performed. The primary endpoint was the decline in mean BP after anesthetic administration in telmisartan and valsartan groups. Multivariate logistic regression analysis was used to identify predictors of post-induction hypotension.

RESULTS

Data from 157 patients undergoing noncardiac surgery were analyzed. No significant differences were found in mean BP decline between the two groups during anesthesia induction. Hemodynamic changes and LV ejection fraction (EF) during anesthesia induction were similar between the groups. Age and preoperative initial mean BP in operation room (OR) were associated with post-induction hypotension in both groups.

CONCLUSIONS

The angiotensin receptor blocker (ARB) type did not influence post-induction hypotension during anesthesia induction. Age and preoperative initial mean BP in OR were associated with post-induction hypotension in patients taking ARBs.

Nitroxyl: A Novel Strategy to Circumvent Diabetes Associated Impairments in Nitric Oxide Signaling

Diabetes is associated with an increased mortality risk due to cardiovascular complications. Hyperglycemia-induced oxidative stress underlies these complications, leading to an impairment in endogenous nitric oxide (NO•) generation, together with reductions in NO• bioavailability and NO• responsiveness in the vasculature, platelets and myocardium. The latter impairment of responsiveness to NO•, termed NO• resistance, compromises the ability of traditional NO•-based therapeutics to improve hemodynamic status during diabetes-associated cardiovascular emergencies, such as acute myocardial infarction. Whilst a number of agents can ameliorate (e.g. angiotensin converting enzyme [ACE] inhibitors, perhexiline, statins and insulin) or circumvent (e.g. nitrite and sGC activators) NO• resistance, nitroxyl (HNO) donors offer a novel opportunity to circumvent NO• resistance in diabetes. With a suite of vasoprotective properties and an ability to enhance cardiac inotropic and lusitropic responses, coupled with preserved efficacy in the setting of oxidative stress, HNO donors have intact therapeutic potential in the face of diminished NO• signaling. This review explores the major mechanisms by which hyperglycemia-induced oxidative stress drives NO• resistance, and the therapeutic potential of HNO donors to circumvent this to treat cardiovascular complications in type 2 diabetes mellitus.

Leptin and interleukin-6 level in patients with hypertension and obesity combined with non-alcoholic steatohepatitis during treatment with sartans and statins

The results of treatment of patients with arterial hypertension and obesity combined with non-alcoholic steatohepatitis are presented in article. Herein, the combined use of olmesartan or telmisartan with atorvastatin for 12 weeks had a positive impact on the physical condition of patients with arterial hypertension and obesity. This effect was manifested by maintenance of optimal blood pressure, the reduction of subjective complaints and the improvement of heart hemodynamics. Administration of sartans and statins to patients with arterial hypertension combined with obesity and non-alcoholic steatohepatitis led to a significant reduction of LDL (p<0.01) and LDL cholesterol levels (p<0.01), as well as the values of leptin (p<0.01) and IL-6 (p<0.01). The combination of olmesartan or telmisartan with atorvastatin not only allows a control of BP, but also a reduction of the pro-atherogenic fractions of blood lipids, hyperleptinaemia and levels of pro-inflammatory IL-6, hence, in this manner, improving the patient general condition.

Candesartan cilexetil prevents diet-induced insulin resistance via peroxisome proliferator-activated receptor-γ activation in an obese rat model

Angiotensin II type 1 receptor (AT1R) blockers (ARBs) have been shown to reduce the incidence of type 2 diabetes mellitus; however, the underlying molecular mechanism is unknown. Peroxisome proliferator-activated receptor γ (PPARγ) is the central regulator of insulin and glucose metabolism, which improves insulin sensitivity. Whether candesartan cilexetil, as a prodrug of the AT1R blocker candesartan, has PPARγ-activating properties remains to be elucidated. The aim of the present study was to investigate the effects of oral administration of candesartan cilexetil on glucose tolerance and the actions of PPARγ on liver and adipose tissue in the insulin-resistant obese rat induced by high-fat diet. Animals treated with candesartan cilexetil showed an improved glucose tolerance after oral glucose challenge. Whole-body insulin sensitivity was evaluated using the hyperinsulinemic-euglycemic clamp technique. During high-fat feeding in high-fat diet (HF) rats, the glucose infusion rate (GIR) was 52.3% lower than that in normal chow (NC) rats. However, the GIR was significantly enhanced following candesartan cilexetil treatment. Angiotensin II receptor antagonism also resulted in significant increases in PPARγ protein expression in adipose and liver tissue. These results indicate that PPARγ activation by candesartan cilexetil may provide novel therapeutic options in the treatment of patients with metabolic syndrome.

Relationship between patients' knowledge and medication adherence among patients with hypertension

OBJECTIVE

The purpose of this study was to investigate the relationship between knowledge on arterial hypertension (AH) and its management, and adherence to pharmaceutical treatment.

METHODS

The study included 233 patients diagnosed with AH and treated with hypotensive drugs for at least 1 year. The 8-item © Morisky Medication Adherence Scale (MMAS-8) and the Hypertension Knowledge-Level Scale (HK-LS) were used.

RESULTS

Sixty-three percent of the patients had a low level of knowledge on AH, with the smallest proportion of correct answers provided for items related to non-pharmaceutical treatment, diet, hypertension definition, and drug adherence. When compared to patients with a high level of knowledge, those with a low knowledge had lower scores in the MMAS (6.45±1.45 vs 7.08±1.04; P=0.038). Multiple-factor analysis showed that statistically significant independent determinants of good adherence included a high level of knowledge (β=0.208; P=0.001), non-pharmaceutical treatment (β=0.182; P=0.006), and frequent blood pressure measurements (β=0.183; P=0.004). The most significant factor in MMAS was knowledge in the "drug adherence" domain (ρ=0.303; P<0.001).

CONCLUSION

Patients' knowledge on hypertension is a significant independent determinant of good adherence. Other independent determinants include non-pharmaceutical treatment and regular blood pressure measurements.

IMPLICATION FOR PRACTICE

The identification of knowledge deficits as a factor contributing to lack of adherence and poor hypertension control remains a key challenge for multidisciplinary team caring for patients with hypertension.

DanQi Pill protects against heart failure through the arachidonic acid metabolism pathway by attenuating different cyclooxygenases and leukotrienes B4

Background

Chinese herbal formulae are composed of complex components and produce comprehensive pharmacological effects. Unlike chemical drugs that have only one clear single target, the components of Chinese herbal formulae have multiple channels and targets. How to discover the pharmacological targets of Chinese herbal formulae and their underlying molecular mechanism are still under investigation.

Methods

DanQi pill (DQP), which is one of the widely prescribed traditional Chinese medicines, is applied as an example drug. In this study, we used the drug target prediction model (DrugCIPHER-CS) to examine the underlying molecular mechanism of DQP, followed by experimental validation.

Results

A novel therapeutic effect pattern of DQP was identified. After determining the compounds in DQP, we used DrugCIPHER-CS to predict their potential targets. These potential targets were significantly enriched in well-known cardiovascular disease-related pathways. For example, the biological processes of neuroactive ligand–receptor interaction, calcium-signaling pathway, and aminoacyl–tRNA biosynthesis were involved. A new and significant pathway, arachidonic acid (AA) metabolism, was also identified in this study. This predicted pathway alteration was validated with an animal model of heart failure (HF). Results show that DQP had effect both on thromboxane B2 (TXB2) and Prostaglandin I2 (PGI2) in different patterns. It can down-regulate the TXB2 and up-regulate the PGI2 in diverse way. Remarkably, it also had effect on cyclooxygenase (COX)-1 and COX2 by suppressing their levels, which may be the critical and novel mechanism of cardiacprotective efficacy for DQP. Furthermore, leukotrienes B4 (LTB4) receptor, another key molecule of AA metabolism which finally mediated gastrotoxic leukotrienes, was also reduced by DQP.

Conclusions

The combination of drug target prediction and experimental validation provides new insights into the complicated mechanism of DQP.

Elevated 18F-FDG levels in blood and organs after angiotensin II receptor blocker administration: experiment in mice administered telmisartan

Angiotensin II receptor blockers (ARBs) are a common treatment for hypertensive patients but affect renal function. In this study, the effects of ARB on (18)F-FDG distribution and excretion were examined in mice treated with telmisartan at different doses.

METHODS

Male C57BL/6J mice were given telmisartan (low-dose group, 0.33 mg/kg/d; moderate-dose group, 0.66 mg/kg/d; high-dose group, 3 mg/kg/d) mixed in a high-fat diet for 20 wk. Mice on a telmisartan-free diet served as the control. At designated time points, the mice were injected with (18)F-FDG (18.5 MBq/mouse, n = 5-10/time point for each group) to examine its biodistribution. Autoradiography using kidney sections was performed to visualize (18)F-FDG excretion. Plasma blood urea nitrogen (BUN) and creatinine levels were also measured to evaluate renal function.

RESULTS

Twenty-week telmisartan treatment significantly and dose-dependently increased (18)F-FDG levels in the blood (percentage injected dose per gram of tissue normalized by animal body weight: low, 0.13 ± 0.03 [P < 0.0083]; moderate, 0.15 ± 0.01 [P < 0.0083]; high, 0.15 ± 0.03 [P < 0.0083], vs. control, 0.09 ± 0.01). Significantly increased (18)F-FDG levels in organs were observed in mice in the moderate- and high-dose groups but not in the low-dose group. The plasma BUN and creatinine levels also dose-dependently increased, but they were within the reference ranges (for BUN: low, 27.00 ± 4.42 mg/dL; moderate, 28.40 ± 2.70 mg/dL; high, 39.22 ± 6.91 mg/dL [P < 0.0083], vs. control, 22.40 ± 2.80 mg/dL. For creatinine: low, 0.28 ± 0.11 mg/dL; moderate, 0.40 ± 0.07 mg/dL [P < 0.0083]; high, 0.51 ± 0.09 mg/dL [P < 0.0083], vs. control, 0.18 ± 0.04 mg/dL). The blood (18)F-FDG level positively correlated with plasma BUN (r = 0.48, P < 0.01) and creatinine (r = 0.61, P < 0.01) levels. The (18)F-FDG levels in the blood and organs returned to baseline 3 wk after cessation of telmisartan treatment. Autoradiography indicated that renal (18)F-FDG excretion was attenuated by telmisartan treatment and was reversed after treatment cessation.

CONCLUSION

(18)F-FDG levels in the blood and organs were significantly increased by telmisartan treatment, indicating a potential increase in background activity on PET imaging of patients treated with ARBs. Our findings indicate the need for a careful assessment of (18)F-FDG uptake in patients treated with ARBs. A brief cessation of ARB treatment may be a potential method to avoid these effects and solve this problem.

Targeting the upregulation of reactive oxygen species subsequent to hyperglycemia prevents type 1 diabetic cardiomyopathy in mice

Cardiac oxidative stress is an early event associated with diabetic cardiomyopathy, triggered by hyperglycemia. We tested the hypothesis that targeting left-ventricular (LV) reactive oxygen species (ROS) upregulation subsequent to hyperglycemia attenuates type 1 diabetes-induced LV remodeling and dysfunction, accompanied by attenuated proinflammatory markers and cardiomyocyte apoptosis. Male 6-week-old mice received either streptozotocin (55mg/kg/day for 5 days), to induce type 1 diabetes, or citrate buffer vehicle. After 4 weeks of hyperglycemia, the mice were allocated to coenzyme Q10 supplementation (10mg/kg/day), treatment with the angiotensin-converting-enzyme inhibitor (ACE-I) ramipril (3mg/kg/day), treatment with olive oil vehicle, or no treatment for 8 weeks. Type 1 diabetes upregulated LV NADPH oxidase (Nox2, p22(phox), p47(phox) and superoxide production), LV uncoupling protein UCP3 expression, and both LV and systemic oxidative stress (LV 3-nitrotyrosine and plasma lipid peroxidation). All of these were significantly attenuated by coenzyme Q10. Coenzyme Q10 substantially limited type 1 diabetes-induced impairments in LV diastolic function (E:A ratio and deceleration time by echocardiography, LV end-diastolic pressure, and LV -dP/dt by micromanometry), LV remodeling (cardiomyocyte hypertrophy, cardiac fibrosis, apoptosis), and LV expression of proinflammatory mediators (tumor necrosis factor-α, with a similar trend for interleukin IL-1β). Coenzyme Q10's actions were independent of glycemic control, body mass, and blood pressure. Coenzyme Q10 compared favorably to improvements observed with ramipril. In summary, these data suggest that coenzyme Q10 effectively targets LV ROS upregulation to limit type 1 diabetic cardiomyopathy. Coenzyme Q10 supplementation may thus represent an effective alternative to ACE-Is for the treatment of cardiac complications in type 1 diabetic patients.

Interactions of the potent synthetic AT1 antagonist analog BV6 with membrane bilayers and mesoporous silicate matrices

The present work describes the drug:membrane interactions and a drug delivery system of the novel potent AT1 blocker BV6. This designed analog has most of the pharmacological segments of losartan and an additional biphenyltetrazole moiety resulting in increased lipophilicity. We found that BV6:membrane interactions lead to compact bilayers that may in part explain its higher in vitro activity compared to losartan since such environment may facilitate its approach to AT1 receptor. Its high docking score to AT1 receptor stems from more hydrophobic interactions compared to losartan. X-ray powder diffraction (XRPD) and thermogravimetric analysis (TGA) have shown that BV6 has a crystalline form that is not decomposed completely up to 600°C. These properties are desirable for a drug molecule. BV6 can also be incorporated into a mesoporous silicate drug-delivery matrix SBA-15. The properties of the obtained drug-delivery system have been inspected by XRD, (13)C CP/MAS, TGA and nitrogen sorption experiments.

Organic nitrates favor regression of left ventricular hypertrophy in hypertensive patients on chronic peritoneal dialysis

The aim of the study was to evaluate the effect of nitrates on left ventricular hypertrophy (LVH) in hypertensive patients on chronic peritoneal dialysis (PD). Sixty-four PD patients with hypertension were enrolled in this study. All patients accepted antihypertensive drugs at baseline. Thirty-two patients (nitrate group) took isosorbide mononitrate for 24 weeks. The remaining 32 patients (non-nitrate group) took other antihypertensive drugs. Blood pressure (BP), left ventricular mass index (LVMI) and plasma asymmetric dimethylarginine (ADMA) were monitored. Subjects with normal renal function were included as the control group (n = 30). At baseline, plasma ADMA levels in PD patients were significantly higher than the control group, but there was no significant difference in plasma ADMA levels between the two groups. At the end of the 24-week period, BP, LVMI, LVH prevalence and plasma ADMA levels in the nitrate group were significantly lower than those in the non-nitrate group. BP did not show a significant difference between 12 and 24 weeks in the nitrate group with a reduced need for other medication. Logistic regression analysis showed that nitrate supplementation and SBP reduction were independent risk factors of LVMI change in PD patients after adjusting for age, gender, diabetes history and CCB supplementation. It was concluded that organic nitrates favor regression of LVH in hypertensive patients on chronic peritoneal dialysis, and nitrates may be considered for use before employing the five other antihypertensive agents other than nitrates.

Telmisartan 80 mg/hydrochlorothiazide 25 mg single-pill combination in the treatment of hypertension

INTRODUCTION

International guidelines emphasize the importance of blood pressure (BP) control to reduce cardiovascular risk. Telmisartan, an angiotensin II receptor blocker, provides large BP reductions and also prevents cardiovascular events in patients at high risk. The thiazide diuretic, hydrochlorothiazide (HCTZ), has a complementary mode of action, and combination with telmisartan is an established and rational treatment option for patients uncontrolled on monotherapy. A single-pill combination (SPC) of telmisartan 80 mg with high-strength HCTZ 25 mg (T80/H25) is widely available.

AREA COVERED

Clinical data on T80/H25 SPC for the management of hypertension was identified via MEDLINE searches. T80/H25 SPC provides greater BP reductions and higher goal achievement rates in patients who cannot achieve BP goal with T80/HCTZ 12.5 mg SPC, and also as initial therapy compared with T80 monotherapy. T80/H25 also reduced BP significantly more than valsartan 160 mg/H25 combination, and demonstrated favorable tolerability in clinical trials.

EXPERT OPINION

Patients with hypertension often do not achieve BP goal, even when treated, leaving them at increased cardiovascular risk. In part this is due to poor adherence, which can be exacerbated by treatment side effects. High BP goal achievement with SPC T80/H25, with maintained tolerability, provides a treatment option for increasing BP control.

Comparison of the efficacy and safety profiles of two fixed-dose combinations of antihypertensive agents, amlodipine/benazepril versus valsartan/hydrochlorothiazide, in patients with type 2 diabetes mellitus and hypertension: a 16-week, multicenter, randomized, double-blind, noninferiority study

BACKGROUND

Hypertension is a prevalent condition that is closely associated with chronic complications in patients with diabetes. Fixed-dose combination therapy is currently recommended for the treatment of hypertension due to the advantage of reducing the pill burden. However, the effects of combination therapy may be diverse because of the different components.

OBJECTIVES

We examined blood pressure reduction and metabolic alterations after amlodipine/benazepril and valsartan/hydrochlorothiazide treatment in patients with type 2 diabetes mellitus and hypertension and microalbuminuria.

METHODS

This randomized, double-blind, parallel comparison, noninferiority clinical trial included patients with type 2 diabetes mellitus and hypertension and microalbuminuria detected within the past year. After a 2-week, placebo run-in period, patients were assigned to treatment with amlodipine/benazepril or valsartan/hydrochlorothiazide for 16 weeks. The primary end point was mean change in diastolic blood pressure. The prespecified boundary for noninferiority was 3.5 mm Hg of the mean change in diastolic blood pressure between treatments (amlodipine/benazepril minus valsartan/hydrochlorothiazide). If the upper limit of the 95% CI fell within 3.5 mm Hg, amlodipine/benazepril would be considered noninferior to valsartan/hydrochlorothiazide.

RESULTS

Of the 226 patients assessed for eligibility, 169 satisfied the inclusion/exclusion criteria and were assigned to a treatment group; 83 patients (54.2% male, mean age of 60.5 [10.0] years) in the amlodipine/benazepril group and 84 patients (64.3% male, mean age of 59.0 [10.6] years) in the valsartan/hydrochlorothiazide group received at least 1 dose of study medication and were included in the intention-to-treat population. In the per-protocol population, amlodipine/benazepril (n = 74) was noninferior to valsartan/hydrochlorothiazide (n = 78) with regard to the mean change in diastolic blood pressure (difference, -0.9 mm Hg; 95% CI, -3.5 to 1.6). The mean change in systolic blood pressure was not significantly different (2.4 mm Hg; 95% CI, -1.2 to 6.0) between study groups (P = 0.195) in the per-protocol population. However, data from the intention-to-treat population suggest that patients in the amlodipine/benazepril group may have better metabolic outcomes than those in the valsartan/hydrochlorothiazide group; specifically, a preservation of the estimated glomerular filtration rate (5.7 mL/min/1.73 m(2) [95% CI, 1.9 to 9.6]; P = 0.004) and improvements in glycosylated hemoglobin (-0.5% [95% CI, -0.7 to -0.2]; P < 0.001), fasting triglycerides (-0.4 mmol/L [95% CI, -0.7 to -0.2]; P = 0.002), HDL-C (0.07 mmol/L [95% CI, 0.01 to 0.12]; P = 0.022), and uric acid (-57.5 μmol/L [95% CI, -74.8 to -40.3]; P < 0.001). There were no significant differences in adverse effects between groups, with the exception of more respiratory disorders in the amlodipine/benazepril group than in the valsartan/hydrochlorothiazide group (17 vs 5; P = 0 .006).

CONCLUSIONS

The study results suggest that amlodipine/benazepril is noninferior to valsartan/hydrochlorothiazide with regard to blood pressure reduction and that this combination exerts beneficial effects on renal function, glucose control, HDL-C, and triglyceride levels compared with valsartan/hydrochlorothiazide. However, respiratory adverse events (particularly coughing) were more frequently reported in the amlodipine/benazepril group. ClinicalTrials.gov identifier: NCT01375322.

Drug target prediction based on the herbs components: the study on the multitargets pharmacological mechanism of qishenkeli acting on the coronary heart disease

In this paper, we present a case study of Qishenkeli (QSKL) to research TCM's underlying molecular mechanism, based on drug target prediction and analyses of TCM chemical components and following experimental validation. First, after determining the compositive compounds of QSKL, we use drugCIPHER-CS to predict their potential drug targets. These potential targets are significantly enriched with known cardiovascular disease-related drug targets. Then we find these potential drug targets are significantly enriched in the biological processes of neuroactive ligand-receptor interaction, aminoacyl-tRNA biosynthesis, calcium signaling pathway, glycine, serine and threonine metabolism, and renin-angiotensin system (RAAS), and so on. Then, animal model of coronary heart disease (CHD) induced by left anterior descending coronary artery ligation is applied to validate predicted pathway. RAAS pathway is selected as an example, and the results show that QSKL has effect on both rennin and angiotensin II receptor (AT1R), which eventually down regulates the angiotensin II (AngII). Bioinformatics combing with experiment verification can provide a credible and objective method to understand the complicated multitargets mechanism for Chinese herbal formula.

Telmisartan versus valsartan in patients with hypertension: effects on cardiovascular, metabolic, and inflammatory parameters

Background and Objectives

Angiotensin-receptor blockers (ARBs) have beneficial effects on cardiovascular, metabolic, and inflammatory parameters in addition to controlling blood pressure (BP). However, few comparative clinical studies have been conducted with different ARBs. We compared these effects in patients with uncomplicated hypertension who were receiving telmisartan or valsartan.

Subjects and Methods

The subjects were patients with essential hypertension (48.4±9.6 years) who were randomly assigned to take either telmisartan (80 mg/day, n=30) or valsartan (160 mg/day, n=30) for 12 weeks. Their anthropometric, laboratory, vascular, and echocardiographic data were measured at baseline and at the end of the study.

Results

Baseline characteristics were not significantly different between the two groups, except for the carotid-femoral pulse wave velocity (cfPWV; telmisartan group vs. valsartan group; 841.2±131.0 vs. 761.1±104.4 cm/s, p<0.05). After 12 weeks, BP had fallen to a similar extent with mean reductions in the systolic and diastolic BP of 20.7±18.1 and 16.3±13.0 mm Hg (p<0.001, respectively) for the telmisartan and 22.5±17.0 and 16.8±9.3 mm Hg (p<0.001, respectively) for the valsartan group. Although the cfPWV and left ventricular mass index (LVMI) fell significantly only with the administration of telmisartan, they were not significantly different when baseline cfPWV was considered. The differences in the cfPWV and LVMI changes from baseline between the two groups were also not significant after adjusting for baseline cfPWV. No significant changes in other vascular, metabolic, or inflammatory parameters were observed with either treatment.

Conclusion

The effects of a 12-week treatment with the two ARBs, telmisartan and valsartan, on cardiovascular, metabolic, and inflammatory parameters were not different in patients with uncomplicated hypertension.

Developmental changes in AT1 and AT2 receptor-protein expression in rats

It has long been known that angiotensin type-1 receptors (AT1R) play a critical role in sympathetic regulation, cardiovascular activity, and hormone secretion under physiological and pathological states. On the other hand, the functional significance of angiotensin type-2 receptors (AT2R) is poorly understood. In a recent study we demonstrated that, in rats with chronic heart failure, AT1R protein expression was increased but AT2R expression was decreased in the rostral ventrolateral medulla (RVLM). This imbalance of angiotensin receptors contributed to sympatho-excitation in the heart failure state. In the current experiment, we measured AT1R and AT2R protein expressions in the brainstem, kidney and liver from male foetuses (3 days before birth), male neonates (3 days after birth), male and female adults (8 weeks) and male aged (28 months) rats by Western blot analysis. In the brainstem, we found that the foetuses and neonates exhibited a significantly lower AT2R protein expression compared with adult rats (foetus 0.08 ± 0.01, neonate 0.12 ± 0.01, male adult 0.25 ± 0.01, female adult 0.22 ± 0.02; n = 4 per group, p < 0.001 foetus and neonate compared with male or female adults). In contrast, the foetuses and neonates expressed significantly higher AT1R protein than that of the adults (foetus 0.64 ± 0.09, neonate 0.56 ± 0.01, male adult 0.13 ± 0.02, female adult 0.08 ± 0.02; n = 4 each group, p < 0.001 foetus and neonate compared with male and female adults). In the liver, the AT2R protein was also higher in foetus and neonate, than in adult rats. Interestingly, the foetal liver expressed higher AT1R protein compared with that of the neonate. In the kidney, AT2R expression was significantly increased with age (foetus 0.08 ± 0.01, neonate 0.19 ± 0.02, male adult 0.49 ± 0.04, female adult 0.90 ± 0.10; n = 4 per group, p < 0.01-0.001). AT1R expression, on the other hand, was higher in the foetuses than that in both neonate and male adults. This study provides data contrary to existing dogma that AT2R expression is higher in foetal life and low in adults, suggesting an involvement of a potentially important functional role for AT2R in adult animals and AT1R in foetal development and/or physiology.