Rulka C A, Hamm M W
Department of Nutrition, Rutgers University, New Brunswick, NJ 08903.
J Nutr. 1988 Nov;118(11):1304-10. doi: 10.1093/jn/118.11.1304.
We have investigated the effect of dietary fat on isoproterenol-stimulated and propranolol-inhibited heart rate in the rat. In the first experiment, weanling male Sprague-Dawley rats were fed diets containing 10% butter (10B), 10% corn oil (10C) or 9% butter/1% corn oil (10M) for 4 wk. Heart rate was determined in response to increasing i.v. doses of isoproterenol. The percent stimulation at the highest dose of isoproterenol (100 microM) was found to be significantly higher (P less than 0.05) in the 10C-fed group than either the 10B- and 10M-fed groups. A similar study investigated the effect of propranolol inhibition of heart rate in low-fat (10C and 10B) as well as high-fat (25C) corn oil- and high-fat (25B) butter-fed animals. Heart rate was elevated with a constant i.v. infusion of isoproterenol and the inhibitory effect of propranolol was determined. The ED50 was found not to depend on the level of fat, but was found to be significantly lower in the corn oil-fed animals than in those red butter fat (P less than 0.05). Thus, animals appear to be more sensitive to these beta-adrenergic agonists/antagonists when fed a diet containing corn oil rather than butter fat as the lipid source.
我们研究了膳食脂肪对异丙肾上腺素刺激及普萘洛尔抑制大鼠心率的影响。在第一个实验中，将断乳雄性斯普拉格 - 道利大鼠分别喂食含10%黄油（10B）、10%玉米油（10C）或9%黄油/1%玉米油（10M）的饲料4周。通过静脉注射递增剂量的异丙肾上腺素来测定心率。结果发现，在最高剂量异丙肾上腺素（100微摩尔）时，喂食10C饲料的组的刺激百分比显著高于喂食10B和10M饲料的组（P < 0.05）。一项类似研究调查了普萘洛尔对低脂（10C和10B）以及高脂（25C）玉米油喂养和高脂（25B）黄油喂养动物心率的抑制作用。通过静脉持续输注异丙肾上腺素使心率升高，然后测定普萘洛尔的抑制作用。发现半数有效剂量（ED50）不取决于脂肪水平，但喂食玉米油的动物的ED50显著低于喂食黄油脂肪的动物（P < 0.05）。因此，当动物以含玉米油而非黄油脂肪作为脂质来源的饲料喂养时，它们似乎对这些β - 肾上腺素能激动剂/拮抗剂更敏感。
