摘要目的:观察不同碘营养水平泌乳期大鼠尿碘含量（UIC）、乳汁碘含量（BMIC）和乳汁碘排出量，探索不同碘营养水平大鼠泌乳期碘代谢情况。方法:将40只雌性Wistar大鼠按体重（70 ~ 120 g）采用随机数字表法分为低碘（LI）组、适碘（NI）组、高碘Ⅰ（HIⅠ）组、高碘Ⅱ（HIⅡ）组，每组10只，均食用低碘饲料，分别饮用含碘离子0、325、18 700、37 450 μg/L的去离子水。20只雄鼠按照NI组饲养方式喂养。干预8周后将雄鼠和雌鼠按1∶2比例合笼交配，在雌鼠泌乳期的第7、14、21天（L7、L14、L21）收集乳汁和24 h尿液，并记录进食量及饮水量，采用急性哺乳试验推算24 h乳汁排出量，电感耦合等离子体质谱（ICP-MS）法测定UIC、BMIC。结果:LI、NI、HIⅠ、HIⅡ组泌乳期大鼠24 h总碘摄入量分别为（1.84 ± 0.51）、（30.51 ± 6.79）、（765.95 ± 317.41）、（1 654.26 ± 560.55）μg/d，组间比较差异有统计学意义（ P < 0.001）。在L7、L14和L21时，相同时间点不同组别间UIC、BMIC、乳汁碘排出量比较，差异均有统计学意义（ P均< 0.001），HIⅡ组不同时间点BMIC、乳汁碘排出量比较，差异均有统计学意义（ P均< 0.05）。各组24 h乳汁碘排出量分别为（1.23 ± 0.85）、（11.88 ± 5.23）、（207.09 ± 114.51）、（493.67 ± 242.47）μg，24 h乳汁碘排出量占24 h总碘摄入量的比例分别为66.85%、38.94%、27.04%和29.84%。 结论:碘营养适宜时，泌乳期大鼠膳食碘约有39%通过乳汁供给仔鼠。低碘和高碘摄入时乳汁碘排出比例出现相应的升高和降低，提示不同碘营养水平的泌乳期大鼠通过自身的代偿作用调节乳汁碘的排出比例，以减轻碘缺乏和碘过量对后代的影响。

abstractsObjective:To observe the urinary iodine content (UIC), breast milk iodine content (BMIC) and milk iodine excretion of lactating rats under different iodine nutrition levels, and to explore the iodine metabolism of the lactating rats under different iodine nutrition levels.Methods:Forty female Wistar rats with body weight ranging from 70 to 120 g were divided into low iodine (LI) group, normal iodine (NI) group, hight iodineⅠ (HIⅠ) group and hight iodine Ⅱ (HIⅡ) group according to body weight by random number table method, with 10 rats in each group. The rats were fed low-iodine diet, and the iodine ion concentration of drinking water in each group was 0, 325, 18 700 and 37 450 μg/L. Twenty male rats were fed according to the feed method of NI group. After 8 weeks of intervention, the male and female rats were caged and mated in a ratio of 1 ∶ 2. Milk and 24 h urine were collected on the 7th, 14th and 21st days of lactation (L7, L14 and L21), and the amount of food and drinking water consumed were recorded. The 24 h milk excretion was calculated by acute lactation test. UIC and BMIC were determined by inductively coupled plasma mass spectrometry (ICP-MS).Results:The 24 h total iodine intake of lactating rats in LI, NI, HIⅠ and HIⅡ groups were (1.84 ± 0.51), (30.51 ± 6.79), (765.95 ± 317.41) and (1 654.26 ± 560.55) μg/d, respectively. The difference between groups was statistically significant ( P < 0.001). At L7, L14 and L21, there were statistically significant differences in UIC, BMIC and milk iodine excretion at the same lactation stages among different groups ( P < 0.001). In HIⅡ group, the difference of BMIC and milk iodine excretion at different lactation stages (L7, L14, and L21) were significantly signrficant ( P < 0.05). The 24 h milk iodine excretion of LI, NI, HIⅠ and HIⅡ groups was (1.23 ± 0.85), (11.88 ± 5.23), (207.09 ± 114.51), (493.67 ± 242.47) μg, respectively. The proportion of 24 h milk iodine excretion to 24 h total iodine intake was 66.85%, 38.94%, 27.04% and 29.84%, respectively. Conclusions:About 39% of dietary iodine is supplied to offspring through milk when iodine nutrition is normal. The iodine excretion ratio of milk is increased or decreased with low and high iodine levels. These results indicate that lactating rats with different iodine nutrition levels can regulate the ratio of iodine excretion in milk through their own compensatory effect to reduce the influence of iodine deficiency and iodine excess on their offspring.