Fat intake modifies vascular responsiveness and receptor expression of vasoconstrictors : Implications for diet-induced obesity

Angiotensin II (Ang II), endothelin-1 (ET-1) and reactive oxygen species (ROS) have been implicated in the development of pathologic changes associated with obesity including hypertension and atherosclerosis. The aim of this study was to investigate the effects of dietary fat content on vasoreactivity and receptor expression at the level of gene and protein expression. C57BL/6 mice were fed diets of normal (Control, 12.3% kcal from fat), high (HF, 41% kcal from fat) and very high (VHF, 58% kcal from fat) fat content for 15 weeks. Glucose tolerance tests were performed, and aortic rings were exposed to ET-1 (0.01-300 nM) and Ang II (100 nM) in the presence of L-nitro-arginine-methyl ester (L-NAME; 300 microM). Gene and protein expressions of angiotensin and endothelin receptors were examined by real-time PCR and immunoblotting, respectively. The effects of diet on responses to acetylcholine (ACh 0.1-300 microM), in the absence or presence of L-NAME, and to exogenous ROS/.OH were also investigated. Both high fat diets similarly impaired glucose tolerance (P