Angiotensin II receptor blockers downsize adipocytes in spontaneously type 2 diabetic rats with visceral fat obesity

Objective: To investigate the influence of blockade of the renin-angiotensin system (RAS) on adipocytes, we compared the effect of telmisartan versus valsartan and amlodipine on adipocyte cellularity in the spontaneously type 2 diabetic, obese rat model. Methods: Male Otsuka Long Evans Tokushima Fatty rats, 8-week-old, were divided into four groups as follows: valsartan (V) group (10 mg/kg, n = 12), telmisartan (T) group (5 mg/kg, n = 12), amlodipine (A) group (2 mg/kg, n = 12), and control (C) group (n = 12). Each drug was mixed with chow and given for 16 weeks. Results: Although no significant differences were observed in the fasting plasma glucose level between the groups, the fasting plasma insulin level for group T was significantly lower than that for group C. Histopathologic examination showed that the ratio of small adipocytes in groups V and T was significantly higher than that in group C, with the ratio of large adipocytes and the mean adipocyte size shown to be significantly lower in groups V and T than in group C. Furthermore, group T was shown to have a significantly higher ratio of small adipocytes, a significantly lower ratio of large adipocytes, as well as a significantly lower mean adipocyte size, compared to group V. Conclusions: Although both valsartan and telmisartan downsized adipocytes, adipocyte downsizing was significantly greater with telmisartan compared to valsartan. The likely mechanism for this difference was thought to be the PPAR-gamma-mediated action of telmisartan.