Weiping Li, Qingfeng Cheng, Shikun Ma, Xiurong Liu, Hua Qin, Xiaoshu Bai, Suhua Zhang, Qifu Li
Department of Endocrinology, First Affiliated Hospital, Chongqing Medical University, 1 Youyi Road, 400016, Chongqing, P. R. China.
Endocrine. 2006 Dec;30(3):283-7. doi: 10.1007/s12020-006-0006-3.
Retinol binding protein 4 (RBP4) is a novel adipocyte-secreted protein that contributes to systemic insulin resistance. Experiments in mice suggest that elevated RBP4 causes insulin resistance. In the present study, we determined serum RBP4 concentration and evaluated its association with insulin resistance in women with polycystic ovarian syndrome (PCOS); 39 PCOS women and 45 healthy control subjects were enrolled in this study. Serum RBP4, fasting plasma glucose (FPG) and fasting serum insulin (FINS) were measured in all subjects. Furthermore, oral glucose tolerance test (OGTT), Botnia clamp (an intravenous glucose tolerance test followed by an euglycemic hyperinsulinemic clamp), and measurements of sex hormones were performed in 13 control subjects and all the PCOS women. The levels of serum RBP4 were elevated in PCOS women compared with the control (11.69 +/- 6.72 versus 7.75 +/- 5.96 microg/mL, p = 0.006). RBP4 levels were positively correlated with WHR (r = 0.216, p = 0.048), and intravenous glucose tolerance test beta cell index (IVGTT-beta index) which reflected beta cell function (r = 0.309, p = 0.028), but were inversely correlated with M value during Botnia clamp, which represented insulin sensitivity (r = -0.362, p = 0.008). No correlation was found between RBP4 and age, BMI, blood pressure, FPG, FINS, 2-h postprandial glucose, 2-h postprandial insulin, free testosterone, total testosterone, follicle-stimulating hormone (FSH), or luteinizing hormone (LH). In a linear stepwise regression analysis with a model including age, BMI, WHR, free testosterone, IVGTT-beta index, and M value as independent variables, only M value showed significant correlation with serum RBP4 levels (r2 = 0.105, f = 6.640, p = 0.012). In conclusion, serum RBP4 levels are significantly increased in PCOS women and associated with insulin resistance, which indicates that RBP4 may be a contributing factor linking adipose tissue with insulin resistance in PCOS.
视黄醇结合蛋白4（RBP4）是一种新的脂肪细胞分泌蛋白，与全身性胰岛素抵抗有关。小鼠实验表明，RBP4升高会导致胰岛素抵抗。在本研究中，我们测定了多囊卵巢综合征（PCOS）女性的血清RBP4浓度，并评估其与胰岛素抵抗的关系；本研究纳入了39名PCOS女性和45名健康对照者。对所有受试者测定血清RBP4、空腹血糖（FPG）和空腹血清胰岛素（FINS）。此外，对13名对照者和所有PCOS女性进行了口服葡萄糖耐量试验（OGTT）、博特尼亚钳夹试验（静脉葡萄糖耐量试验后进行正常血糖高胰岛素钳夹试验）以及性激素测定。与对照组相比，PCOS女性的血清RBP4水平升高（11.69±6.72对7.75±5.96μg/mL，p = 0.006）。RBP4水平与腰臀比（WHR）呈正相关（r = 0.216，p = 0.048），与反映β细胞功能的静脉葡萄糖耐量试验β细胞指数（IVGTT-β指数）呈正相关（r = 0.309，p = 0.028），但与博特尼亚钳夹试验期间代表胰岛素敏感性的M值呈负相关（r = -0.362，p = 0.008）。未发现RBP4与年龄、体重指数、血压、FPG、FINS、餐后2小时血糖、餐后2小时胰岛素、游离睾酮、总睾酮、促卵泡激素（FSH）或促黄体生成素（LH）之间存在相关性。在以年龄、体重指数、WHR、游离睾酮、IVGTT-β指数和M值作为自变量的线性逐步回归分析模型中，只有M值与血清RBP4水平显示出显著相关性（r2 = 0.105，f = 6.640，p = 0.012）。总之，PCOS女性的血清RBP4水平显著升高且与胰岛素抵抗相关，这表明RBP4可能是PCOS中连接脂肪组织与胰岛素抵抗的一个促成因素。
