Ohinata Kousaku, Takemoto Masami, Kawanago Makoto, Fushimi Shuya, Shirakawa Hitoshi, Goto Tomoko, Asakawa Akihiro, Komai Michio
Department of Science of Food Function and Health, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 Japan.
J Nutr. 2009 Mar;139(3):611-6. doi: 10.3945/jn.108.096370. Epub 2009 Jan 21.
We investigated the role of zinc in food intake regulation using rats during early-stage zinc deficiency without decreased zinc concentrations in plasma and tissues. Plasma, liver, and hypothalamic zinc concentrations were not affected in male Sprague-Dawley rats fed a zinc-deficient (Zn-Def) diet for 3 d compared with the pair-fed control group, which was fed a zinc-sufficient diet to the intake of the Zn-Def diet. Zinc sulfate at a dose of 19 micromol/kg body weight was orally or intraperitoneally (i.p.) administered to rats fed a Zn-Def diet for 3d and food intake was measured. We found that zinc stimulated food intake after oral but not i.p. administration. The mRNA expression of neuropeptide Y (NPY) and orexin in the hypothalamus significantly increased 3 h after oral but not i.p. administration of zinc. Pretreatment with an antagonist for the NPY Y(1) receptor or the orexin OX(1) receptor blocked orexigenic activity after oral administration of zinc. The stimulation of food intake by oral administration of zinc was abolished by vagotomy. Taken together, orally administered zinc may stimulate food intake via orexigenic peptides coupled to the afferent vagal stimulation in rats after short-term treatment with a Zn-Def diet.
我们在早期锌缺乏且血浆和组织中锌浓度未降低的大鼠中，研究了锌在食物摄入调节中的作用。与配对喂养对照组相比，雄性Sprague-Dawley大鼠喂食锌缺乏（Zn-Def）饮食3天，其血浆、肝脏和下丘脑锌浓度未受影响，配对喂养对照组喂食锌充足饮食，摄入量与锌缺乏饮食组相同。对喂食锌缺乏饮食3天的大鼠口服或腹腔注射（i.p.）19微摩尔/千克体重的硫酸锌，并测量食物摄入量。我们发现，锌口服给药后刺激食物摄入，但腹腔注射则无此作用。口服锌而非腹腔注射锌3小时后，下丘脑中神经肽Y（NPY）和食欲素的mRNA表达显著增加。用NPY Y(1)受体或食欲素OX(1)受体拮抗剂预处理可阻断口服锌后的促食欲活性。口服锌对食物摄入的刺激作用在迷走神经切断后消失。综上所述，在短期喂食锌缺乏饮食的大鼠中，口服锌可能通过与传入迷走神经刺激相关的促食欲肽来刺激食物摄入。
