Uemura K, Young J B
Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611.
Am J Physiol. 1994 Nov;267(5 Pt 2):R1329-35. doi: 10.1152/ajpregu.1994.267.5.R1329.
Adrenal medullary activity increases with fasting, although a role for diet in the regulation of epinephrine (Epi) secretion is otherwise unknown. The current studies examined the effects of dietary fat on adrenal medullary function in male CD rats. Addition of lard to a lab chow diet (+50% of chow energy) for 4 days lowered Epi excretion by 14% (P = 0.0005). Two weeks' exposure to diet containing 33% lard (by energy) reduced urinary Epi compared with that in animals fed an isoenergetic amount of chow. Epi levels in plasma obtained by indwelling catheter from unanesthetized unrestrained rats were lower in lard-fed rats than in chow-fed controls. The plasma Epi response to intravenous administration of d-fenfluramine (4 mg/kg), however, was exaggerated in the lard-fed rats. Plasma NE levels also rose after d-fenfluramine, but responses did not differ between diet groups. Urinary Epi was also measured after exposure to other fats. Beef tallow, like lard, suppressed Epi excretion, but safflower, medium-chain triglyceride, coconut, and soybean oils did not. These results suggest that fats of animal origin, in contrast to those derived from plants, suppress adrenal medullary function, possibly via alteration in central serotonergic pathways.
禁食时肾上腺髓质活动增强，不过饮食在肾上腺素（Epi）分泌调节中的作用尚不清楚。目前的研究检测了膳食脂肪对雄性CD大鼠肾上腺髓质功能的影响。在实验室常规饲料中添加猪油（占饲料能量的50%）4天，可使Epi排泄量降低14%（P = 0.0005）。与喂食等能量常规饲料的动物相比，接触含33%猪油（按能量计算）的饲料两周可使尿Epi减少。通过留置导管从未麻醉、未束缚的大鼠获取的血浆中，喂食猪油的大鼠的Epi水平低于喂食常规饲料的对照组。然而，喂食猪油的大鼠对静脉注射d-芬氟拉明（4 mg/kg）的血浆Epi反应增强。d-芬氟拉明给药后血浆去甲肾上腺素（NE）水平也升高，但不同饮食组之间的反应没有差异。接触其他脂肪后也测量了尿Epi。牛脂与猪油一样，可抑制Epi排泄，但红花油、中链甘油三酯、椰子油和大豆油则无此作用。这些结果表明，与植物来源的脂肪相比，动物来源的脂肪可能通过改变中枢5-羟色胺能途径来抑制肾上腺髓质功能。
