Obesity and type 2 diabetes (T2D) are major risk factors for cardiovascular diseases. Zucker fatty diabetes mellitus (ZFDM)-Lepr^fa/fa (Homo) rats develop obesity and T2D at a young age, while ZFDM-Lepr^fa/+ (Hetero) rats are normal. We recently reported that blood pressure in Homo is normal until 35 weeks of age, while blood adrenaline level and sympathetic nervous activity are lower than Hetero. In the present study, we tested the hypothesis that contractile reactivity to adrenaline in peripheral blood vessels from Homo increases. After the isolated mesenteric arteries were cumulatively administrated with adrenaline (1 nM-30 μM) in the presence or absence of propranolol (1 μM), isometric tension was measured by a Magnus method. Body weight and blood glucose levels in Homo were significantly higher than Hetero, while heart rate was significantly lower. The adrenaline-induced contraction in the isolated mesenteric artery from Homo was significantly higher than Hetero. In Hetero, pretreatment with propranolol enhanced the adrenaline-induced contraction, while it had no effect in Homo. These results suggest that the adrenaline-induced contraction in the isolated mesenteric artery from Homo may be increased due to the altered expression of adrenaline receptors. In addition, the increased adrenaline responsiveness of peripheral arteries in Homo would maintain the blood pressure normal despite the decrease of sympathetic nerve activity.