青年科学工作者论坛2006年第1期

王重建  杨年红¹  许明佳  武颂文  杨雪锋  刘烈刚  孙秀发

华中科技大学同济医学院公共卫生学院营养与食品卫生系，武汉 430030

摘要：目的 研究高脂饮食诱导肥胖（DIO）及肥胖抵抗（DIO-R）大鼠血浆PYY3-36含量及回结肠PYY mRNA的表达情况，探讨PYY3-36与高脂饮食诱导肥胖抵抗的关系。 方法  36只雌性SD大鼠，按体重随机分为高脂实验组（n=27）和基础对照组（n=9），分别给予高脂饲料和基础饲料喂养13周。据13周末体重将高脂饲料组再分为饮食诱导肥胖（DIO）和饮食诱导肥胖抵抗 （DIO-R）组，比较各组大鼠能量摄入水平、血浆PYY3-36含量及回结肠PYY mRNA表达水平的差异。结果  DIO-R大鼠热能摄入量显著低于DIO大鼠(P<0.01)；与对照组大鼠相比无显著性差异（P>0.05）；DIO-R大鼠血浆PYY3-36含量及回结肠PYY mRNA表达水平显著高于DIO和对照组大鼠(P<0.01)；DIO与对照组相比，除回肠PYY mRNA 表达水平升高外，其余指标均无显著性差异（P>0.05）。结论  高脂饮食条件下，SD大鼠表现为明显的肥胖易感性差异，这种差异可能与PYY3-36的食欲调节密切相关，血浆PYY3-36含量和回结肠PYY mRNA表达水平的升高可能是导致DIO-R大鼠热能摄入下降的内在机制之一。

关键词：高脂饮食  肥胖  肥胖抵抗  热能摄入  PYY3-36

中图分类号：R589.2   R151.3             文献标识码：A

 

Wang Chong-jian，Yang Nian-hong，Xu Ming-jia，Wu Song-wen, et al.

Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430030, China

Abstract:  Objective  To study the plasma concentration of PYY3-36 and the expression levels of PYY mRNA of ileum and colon in dietary induced obesity (DIO) and dietary induced obesity resistant (DIO-R) rats and the relation between PYY3-36 and DIO-R rats.  Methods  Thirty-six female SD rats were randomly divided into high-fat diet group (n=27) and chow fed control group (n=9), after 13 weeks of either a high-fat diet or chew fed diet, the high-fat diet group was subdivided into dietary induced obesity (DIO) and Dietary Induced Obesity Resistant (DIO-R) group according to the final body weight. Weight gain, caloric intake, the concentration of PYY3-36 and the expression levels of PYY mRNA were measured and compared.  Results  The total caloric intake of DIO-R rats was lower than DIO rats (P<0.01)，while no significant difference was found between DIO-R and control rats (P>0.05). The concentration of PYY3-36 and the expressions of PYY mRNA of ileum and colon in DIO-R rats were higher significantly than that of the DIO and control rats (P<0.01), while no significant difference was found between DIO and control group (P>0.05), except that PYY of ileum was advanced in DIO group (P<0.01).  Conclusion  On the High-fat diet, SD rats showed different susceptibility to obese and energy intake, increased levels of PYY3-36 and PYY mRNA might be related to dietary induced obesity resistant.

Key words: high-fat diet, obesity, obesity resistant, caloric intake, peptide YY3-36

 

基金项目：国家自然科学基金项目资助（No.30371213）

作者简介：王重建，男，博士研究生

1通讯作者

青岛大学医学院医学营养学研究所，青岛 266021

 

摘要：目的  在前期对部分中老年农村居民进行了b-胡萝卜素(b-C)转化维生素A(VA)效率评价的基础上，再对10名农村中青年志愿者b-C转化效率进行研究。方法：使用稳定同位素稀释法对10名38~49岁健康志愿者（男5，女5）进行b-C人体代谢实验。2周适应期和56天实验期内，志愿者接受常规膳食，避免大量VA和b-C摄入以及烟、酒和营养制剂。实验第1天，给受试者含6mg氘标记b-C（²H₈ b-C）玉米油胶丸，随半流质早餐（脂肪热能比25%）一起摄入。实验第4天，受试者以同样方法摄入含3mg氘标记醋酸视黄醇(²H_8－ RAc) 油剂胶丸。实验第1天和第4天摄入标记物后0、3、5、7、9、11、13h时，第2、3、5、6、7、8、9、10、14、21、28、35、42、49和56天晨空腹时，采静脉血。用高效液相色谱仪(HPLC)测定血清类胡萝卜素成分浓度，使用气相质谱仪(GC/MS)测定血清中不同来源视黄醇的同位素丰度。根据VA浓度和同位素丰度，描述标记VA在体内应答的血液动力学曲线。结果：10名受试者口服²H₈ b-C和²H₈ RAc后，血清中²H₄视黄醇和²H₈视黄醇的应答反应均非常明显；52天时血清中²H₄视黄醇（来自²H₈ b-C）的曲线下面积（AUC）平均为（1289±547）nmol/d；52天的²H₈视黄醇（来自²H₈-RAC）的AUC平均为（3560±1058）nmol/d；以摄入的²H₈-RAc作为VA参照，计算来自口服²H₈ b-C的²H₄ 视黄醇平均为（3434±1449）nmol/d。b-C转化为VA的转化系数平均为(3.89±2.76) ﹕1(摩尔单位) [范围是(2.00~9.61)﹕1]或者(7.30±5.18)﹕1(质量单位) [范围是(3.76~18.05)﹕1]。结论：采用稳定同位素稀释技术，定量测定了10名中国农村中青年志愿者体内b-C转化为VA的效率，按质量单位计其转化比值平均为7.30﹕1。

关键词：b-胡萝卜素  维生素A  转化效率  同位素稀释法

中图分类号：Q562                             文献标识码：A

 

Qingdao University Medical College, Qingdao 266021, China

Abstract：Objectives  As an extended study of b-Carotene-vitamin A equivalence in Chinese adults, we carried out an experiment on 10 (5 males and 5 females) rural volunteers aged 38-49 years, which would be complementary to the early reported study on subjects aged 50-60 years. Methods  Ten healthy Chinese adult volunteers aged 38-49 years were recruited in a 56 days experiment, which included residency in the Metabolic Research Unit (first 10 days) and in home (last 46 days). A physiological dose of ²H₈ b-C (11011nmol or 6mg) in oil was given with a liquid diet (25% energy from fat) to the volunteers in the first day of the experiment.  Three days after the ²H₈ b-C dose, each volunteer took a reference dose of ²H₈ retinyl acetate (8915nmol or 3mg) in oil with the same liquid diet. Serum samples were collected at 0, 3, 5, 7, 9, 11, 13 hours of the first and the fourth days of study, and fasting serum samples were also collected daily in first 10 days and then weekly at morning of 14th, 21st, 28th, 35th, 42ed, 49th, and 56th day after a 12-hours overnight fast. Serum retinol and carotenoids concentrations were measured by high performance liquid chromatography (HPLC). Also retinol fraction was extracted from serum and isolated by HPLC. The serum retinal enrichments were determined by using gas chromatograph/mass spectrometry with electron capture negative chemical ionization (GC-MS). Results  The average 52-day area under the serum ²H₄ retinol response curve (from the ²H₈ b-C dose) was (1289±547)nmol/d and the 52-day area under the serum ²H₈ retinol response curve (from the ²H₈ retinyl acetate dose) was(3560±1058)nmol/d.  By using ²H₈ retinyl acetate as the vitamin A reference, the ²H₄ retinol formed from ²H₈ b-C (11011nmol) was calculated to be equivalent to (3434±1449)nmol of retinol.  The calculated conversion factor of b-C to retinol ranged from 2.00-9.61 to 1 with an average of 3.89±2.76 to 1 on a molar basis, or 3.76-18.05 to 1 with an average of (7.30±5.18) to 1 on a weight basis. Conclusion  The conversion of b-C to vitamin A in 10 middle-aged Chinese adults had been quantitatively determined by using a stable isotope reference method, and an average conversion ratio of 9.1 to 1 on a weight basis was found in this study.

Key words: b-carotene, retinol, vitamin A, biological conversion efficiency, isotope dilution technique

 

基金项目：国家自然科学基金资助项目(No.30271121)；浙江省科技厅科技项目（No.2005F13026）

作者简介：汪之顼，男，教授，博士

1 山东省济宁市市中区卫生防疫站

2 浙江省医学科学院营养与保健食品所

3 中国疾病预防控制中心营养与食品安全所

周继昌  黄承钰¹  张慧敏²  刘小立²  杨晓光³  朴建华³  贾青  洪君蓉

四川大学华西公共卫生学院营养与食品卫生学教研室，成都  610041

摘要：目的  用铁的稳定性同位素示踪剂评价藏族成年男子膳食铁的吸收率，为该人群及其膳食类型的铁吸收率提供参考数据。方法  于现场进行人体代谢试验，受试者口服稳定性同位素示踪铁剂（浓集⁵⁷Fe的FeSO₄）及稀土元素镝，粪便监测法收集示踪剂排出粪样；用感耦等离子体质谱仪测定粪样⁵⁷Fe/⁵⁶Fe的比值，分析评价该人群膳食铁的吸收率。结果  口服同位素评价藏族成年男子膳食铁的吸收率为13.4%±6.4%；每日示踪剂铁和镝排出呈良好相关性。结论  稀土元素镝与未吸收的示踪剂铁在消化道有一致的排出过程，前者的回收率能很好反映粪样收集情况；藏族成年男子膳食铁的吸收较好。

关键词：藏族  铁  稳定性同位素  吸收率  镝

中图分类号：R151.3                    文献标识码：A

 

Department of Nutrition and Food Hygiene, West China School of Public Health, Sichuan University, Chengdu 610041,China

Abstract：Objective  The study was aimed to evaluate the iron absorption in the Tibetan man’s diet using the stable isotopic iron, and present reference to improve the dietary iron absorption for Chinese.  Methods  In a human metabolism field trial, the iron tracer enriched with ⁵⁷Fe and the recovery indicator dysprosium (Dy) were orally administrated to the subjects of young Tibetan men, and feces were sampled. The ratios of ⁵⁷Fe/⁵⁶Fe in fecal samples were determined with inductively coupled plasma mass spectrometry, and then the iron absorption was calculated based on the theory of isotope dilution.  Results  The dietary iron absorption for Tibetan men was 13.4%±6.4% with good linearity for daily fecal excretions of iron tracer and Dy. Conclusion  Dy had the same behavior as non-absorbed iron tracer in the digestive tract and the recovery of Dy was suggested to represent the completeness of fecal collection. Dietary iron absorption for the adult Tibetan man was relatively high.

Key words: Tibetan, iron, stable isotope, absorption, dysprosium

 

基金项目：国家自然科学基金重点项目（No.39930150）

作者简介：周继昌，男，博士研究生

             1通讯作者

             2深圳市疾病预防控制中心

             3中国疾病预防控制中心营养与食品安全所