胰岛素和胰岛素突变体促进大鼠脂肪细胞摄取葡萄糖

报道了大鼠脂肪细胞摄取葡萄糖测定胰岛素体外活性的简便方法 .在胰岛素存在下 ,脂肪细胞摄取葡萄糖的量比对照增加 5～ 6倍 .当胰岛素浓度在 0 .2～ 1 0μg/L时 ,脂肪细胞摄取D [3 ³H] 葡萄糖的量与胰岛素浓度对数呈线性关系 .葡萄糖和 3 O 甲基葡萄糖抑制指脂肪细胞摄取D [3 ³H]葡萄糖 .利用这一方法测定了[B₂ Lys] 胰岛素和 [B₃ Lys] 胰岛素的体外活力 ,分别为胰岛素的 6 1.6 %和 154% .     

人源FGF-21在脂肪细胞糖代谢中的作用

近年来研究发现,成纤维细胞生长因子(FGF)-21是一种新的代谢调节因子.为了深入研究人源FGF-21（hFGF-21）的生物活性,本实验利用SUMO高效表达载体,高效表达成熟的hFGF-21,并利用小鼠3T3-L1脂肪细胞检测hFGF-21的糖代谢活性．实验结果表明,hFGF-21可促进脂肪细胞的葡萄糖吸收,且葡萄糖吸收效率呈剂量依赖性．hFGF-21作用4 h即可促进脂肪细胞糖吸收,其活性可持续24 h以上．hFGF-21与胰岛素共同作用的葡萄糖吸收效果,明显优于它们的单独作用结果,说明hFGF-21与胰岛素发挥协同作用．脂肪细胞经hFGF-21预处理后,显著增加了胰岛素促进脂肪细胞吸收葡萄糖的效率,说明hFGF-21可以增加胰岛素的敏感性．本实验为临床应用hFGF-21治疗糖尿病,增加胰岛素敏感性提供了依据．     

沙棘籽渣多糖对正常及糖尿病模型动物血糖的影响

本文研究了沙棘籽渣多糖(Polysaccharides from seed residue of Hippophae rhamnoide L.,PSH)对正常小鼠及实验性2型糖尿病大鼠血糖、血脂代谢的影响.以100、200和400 mg/kg剂量的PSH连续灌胃正常小鼠20d;以50和100 mg/kg剂量的PSH连续灌胃由烟酰胺联合链脲佐菌素诱导的类似2型糖尿病大鼠3周,测定血糖、糖基化血清蛋白、血清胰岛素、血清总胆固醇、甘油三酯及肝糖原含量.结果显示:PSH对正常小鼠的血糖和血脂代谢没有明显影响;但能明显降低2型糖尿病大鼠的血清葡萄糖、总胆固醇和糖基化血清蛋白水平,同时显著增加糖尿病大鼠的血清胰岛素含量.上述结果表明:PSH在实验性2型糖尿病大鼠模型上具有降血糖和降胆固醇的活性.     

血小板活化因子对大鼠黄体细胞孕酮分泌及血管内皮生长因子表达的作用

本文旨在研究血小板活化因子(platelet-activating factor,PAF)对大鼠黄体细胞孕酮分泌及血管内皮生长因子(vascularendothelial growth factor,VEGF)mRNA表达的作用.将未成年(25～28 d)Sprague-Dawley雌性大鼠颈部皮下注射50 IU孕马血清促性腺激素(pregnant mare serum gonadotrophin,PMSG),48 h后注射25 IU人绒毛膜促性腺激素(human chorionicgonadotrophin.hCG)诱导卵泡发育和黄体生成,第6天(hCG注射日为第1天)收集卵巢黄体细胞,体外培养24 h后,不加或加入不同剂量(0.1 μg/mL、1 μg/mL、10 μg/mL)PAF,37℃、5%CO2培养箱内培养24 h.用放射免疫方法测定培养液中孕酮的含量,流式细胞仪和RT-PCR方法检测黄体细胞凋亡以及VEGF mRNA的表达.结果显示,PAF促进黄体细胞孕酮分泌,1 μg/mL PAF作用最强(P<0.05);PAF促进黄体细胞凋亡无明显剂量依赖性,但10 μg/mL PAF显著促进大鼠黄体细胞凋亡(P<0.05):PAF刺激黄体细胞VEGF mRNA表达,1 μg/mL PAF效果最显著(P<0.01).结果提示,PAF可通过调节黄体细胞孕酮的分泌和VEGF mRNA的表达来促进黄体形成.     

闹羊花素Ⅲ对斜纹夜蛾细胞系的活性及作用机理

研究了闹羊花素Ⅲ对斜纹夜蛾Spodoptera litura离体培养细胞（SL细胞）的活性,并测定了对SL细胞Na⁺、K⁺和葡萄糖吸收以及对4龄幼虫血细胞数量的影响。结果表明：以400 µg/mL 和200µg/mL闹羊花素Ⅲ处理SL细胞,24 h后细胞的相对死亡率为79.00% 和56.69%,处理后8 h,16 h,24 h和48 h的LC₅₀分别为240.09 µg/mL,173.45 µg/mL,113.56 µg/mL和73.40 µg/mL;闹羊花素Ⅲ处理SL细胞后10 min,细胞对离子的吸收迅速增加,30 min后吸收作用逐渐减弱;处理后3天内细胞对葡萄糖的吸收迅速增加,4～5 天后,细胞对葡萄糖的吸收基本停止。以叶碟法和注射法处理4龄幼虫,8 h后幼虫血细胞数量显著降低,随处理时间增加,幼虫血细胞数量又逐渐增加。     

卡泊芬净、米卡芬净对念珠菌体外药物敏感性的动态研究

目的 动态研究卡泊芬净、米卡芬净体外对念珠菌的药物敏感性.方法 参照CLSI公布的M-27A方案微量液体稀释法分别测定卡泊芬净、米卡芬净、氟康唑对85株念珠菌的体外敏感性,并连续7d观测结果.结果 48 h卡泊芬净对白念珠菌、光滑念珠菌及其他念珠菌MIC50、MIC90中位数分别为0.030μg/mL、0.030 μg/mL,0.060μg/mL、0.125 μg/mL,0.125 μg/mL、0.500 μg/mL.48 h米卡芬净对白念珠菌、光滑念珠菌及其他念珠菌MIC50、MIC90中位数分别为0.030 μg/mL、0.030 μg/mL,0.060 μg/mL、0.060 μg/mL,0.250 μg/mL、0.500 μg/mL.48 h氟康唑对白念珠菌、光滑念珠菌及其他念珠菌MIC80、MIC100中位数分别为2μg/mL、128 μg/mL,64 μg/mL、128 μg/mL,2μg/mL、32μg／mL.85株念珠菌中未见对3种药物同时耐药的菌株.卡泊芬净组白念珠菌MIC50、MIC90 24 h后不再升高;光滑念珠菌MIC50 72 h后不再升高,MIC90 120 h后不再升高;其他念珠菌组MIC50 168 h、MIC90 96 h后不再升高.米卡芬净组白念珠菌、光滑念珠菌MIC50、MIC90 24 h后不再升高;其他念珠菌MIC50、MIC90在72 h后不再升高.结论卡泊芬净、米卡芬净对念珠菌属有较好的抗菌作用,其中对白念珠菌、光滑念珠菌作用更强,且MICs随着作用时间延长而升高并存在药物特异性和念珠菌种属特异性.     

沙棘茶水溶性多糖抗氧化活性的研究

通过还原力、清除超氧阴离子自由基、清除羟自由基和抑制H2O2诱导红细胞氧化溶血实验来评价沙棘茶水溶性多糖(WPHT)体外抗氧化能力,并与Vc进行了比较.结果表明,WPHT具有较强的还原能力,对O-·2和·OH具有较强的清除作用,IC50分别为:394 μg/mL、182 μg/mL;对H2O2诱导红细胞氧化溶血及MDA生成有很强的抑制作用,IC50分别为:221 μg/mL、202 μg/mL.说明WPHT在一定浓度范围内具有较强的抗氧化能力.     

复方沙棘籽油栓对阴道乳杆菌增殖影响的体外研究

目的 了解复方沙棘籽油栓对体外培养的阴道乳杆菌的作用.方法 从中国健康妇女阴道分离乳杆菌进行体外培养,在培养基中加入不同浓度的复方沙棘籽油栓,培养一定时间后,统计各组乳杆菌菌落直径.结果 在药物浓度较低的三组(0.25 mg/mL、1.0 mg/mL和4.0 mg/mL)中,菌落直径与对照组比较差异无统计学意义(P＞0.05);而在药物浓度较高的两组(16 mg/mL、64 mg/mL)中,菌落直径明显较对照组响应时间的菌落直径大,且差异有统计学意义(P＜0.05).结论 阴道乳杆菌在体外培养时,复方沙棘籽油栓可能对其增殖产生一定程度的促增殖作用.     

林可霉素生物合成过程中后期的调控研究

在用林可链霉菌发酵生产林可霉素的过程中,采用FUS-50L多参数全自动发酵罐,通过在线参数、离线参数等的关联分析,发现中后期的调控非常关键.从80h开始补入适量的玉米浆和碳酸钙,可增加三羧酸循环的通量,强化菌体的维持代谢和次级代谢,184h时,发酵液的生物效价由4792 μg/mL(原工艺)增加到7543 μg/mL,(优化工艺);同时,结合生产实际,将50L罐的优化实验结果应用到60 t生产罐实验,184 h时,发酵液的生物效价由4536 μg/mL(原工艺)增加到6582 μg/mL(优化工艺).有效解决了生产后期生物效价增幅很小的问题.     

芦丁对绿豆幼苗营养生长的影响及其与IAA的相互作用

观察了植物体内的天然黄酮芦丁和吲哚乙酸(IAA)对绿豆幼苗营养生长的影响并测定胚轴中的芦丁和IAA含量.光照条件下芦丁(60μg/mL以下)处理对绿豆幼苗生长有一定促进作用,表现为胚轴和主根伸长加快、侧根数目增多、鲜重或干重增加;而光照条件下更高浓度芦丁(80μg/mL以上)处理及黑暗条件下芦丁(20～100μg/mL)处理对绿豆幼苗生长有抑制作用.当培养基中的芦丁浓度为60～80 μg/mL时,光照下的幼苗比暗处理的幼苗在胚轴中积累更多的芦丁;而芦丁浓度为40μg/mL以下和接近100μg/mL时幼苗在光照下累积的芦丁较暗处理的幼苗更少.0.1μg/mL以上的IAA促进芦丁的累积而进一步抑制幼苗胚轴和主根的伸长.当培养基中含有40 μg/mL的芦丁和0.5μg/mL的IAA时,胚轴中累积的芦丁达到高峰.芦丁降低黄化幼苗内源性IAA在胚轴中的累积,并抑制幼苗对IAA的吸收.     

Glucose uptake by adipocytes of obese rats: effect of one bout of acute exercise.

The effect of one bout of acute exercise on impaired glucose metabolism was studied in obese (480 +/- 20 g), untrained rats, at rest (n = 10) and after 60 min of swimming (n = 5). Using the euglycemic, hyperinsulinemic (10 mU.kg-1 x min-1) clamp, glucose clearance rate increased from 7.6 +/- 0.9 at rest to 9.7 +/- 0.5 mL.kg-1 x min-1 after exercise (p < 0.05). Glucose (3-O-[14C]methylglucose) transport (GT) into epididymal adipocytes were incubated with or without insulin. In the absence of insulin, GT was 0.13 +/- 0.02 and 0.26 +/- 0.07 fmol.cell-1 x min-1 at rest and after exercise, respectively. In the presence of insulin (25-1000 microU.mL-1) GT increased at rest from 0.97 +/- 0.08 to 1.13 +/- 0.07 fmol.cell-1 x min-1, and after exercise from 1.35 +/- 0.05 to 1.87 +/- 0.11 fmol.cell-1 x min-1. GT was significantly higher after exercise compared with rest (p < 0.004). At rest, maximal insulin effect was achieved at 100 microU.mL-1, whereas with exercise, GT increased gradually with the insulin dosage. The following may be concluded: (i) the biological effect of insulin is amplified in obese rats by one bout of exercise and (ii) exercise affects GT into enlarged adipocytes by enhancing tissue responsiveness to insulin and by a cellular mechanism unrelated to the insulin action.     

Effects of insulin and norepinephrine on glucose transport and metabolism in rat brown adipocytes. Potentiation by insulin of norepinephrine-induced glucose oxidation

Glucose is an important fuel for rat brown adipose tissue in vivo and its utilization is highly sensitive to insulin. In this study, the different glucose metabolic pathways and their regulation by insulin and norepinephrine were examined in isolated rat brown adipocytes, using [6-14C]glucose as a tracer. Glucose utilization was stimulated for insulin concentrations in the range of 40-1000 microU/ml. Furthermore, the addition of adenosine deaminase (200 mU/ml) or adenosine (10 microM) did not alter insulin sensitivity of glucose metabolism. The major effect of insulin (1 mU/ml) was a respective 7-fold and 5-fold stimulation of lipogenesis and lactate synthesis, whereas glucose oxidation remained very low. The 5-fold stimulation of total glucose metabolism by 1 mU/ml of insulin was accompanied by an 8-fold increase in glucose transport. In the presence of norepinephrine (8 microM), total glucose metabolism was increased 2-fold. This was linked to a 7-fold increase of glucose oxidation, whereas lipogenesis was greatly inhibited (by 72%). In addition, norepinephrine alone did not modify glucose transport. The addition of insulin to adipocytes incubated with norepinephrine, induced a potentiation of glucose oxidation, while lipogenesis remained very low. In conclusion, in the presence of insulin and norepinephrine glucose is a oxidative substrate for brown adipose tissue. However the quantitative importance of glucose as oxidative fuel remains to be determined.     

Subsensitivity to insulin in adipocytes from rats submitted to foot-shock stress

We examined the effect of three daily foot-shock stress sessions on glucose homeostasis, insulin secretion by isolated pancreatic islets, insulin sensitivity of white adipocytes, and glycogen stores in the liver and soleus muscle of rats. Stressed rats had plasma glucose (128.3 +/- 22.9 mg/dL) and insulin (1.09 +/- 0.33 ng/mL) levels higher than the controls (glucose, 73.8 +/- 3.5 mg/dL; insulin, 0.53 +/- 0.11 ng/mL, ANOVA plus Fisher's test; p < 0.05). After a glucose overload, the plasma glucose, but not insulin, levels remained higher (area under the curve 8.19 +/- 1.03 vs. 4.84 +/- 1.33 g/dL 30 min and 102.7 +/- 12.2 vs. 93.2 +/- 16.1 ng/mL 30 min, respectively). Although, the area under the insulin curve was higher in stressed (72.8 +/- 9.8 ng/mL) rats than in control rats (34.9 +/- 6.9 ng/mL) in the initial 10 min after glucose overload. The insulin release stimulated by glucose in pancreatic islets was not modified after stress. Adipocytes basal lipolysis was higher (stressed, 1.03 +/- 0.14; control, 0.69 +/- 0.11 micromol of glycerol in 60 min/100 mg of total lipids) but maximal lipolysis stimulated by norepinephrine was not different (stressed, 1.82 +/- 0.35; control, 1.46 +/- 0.09 micromol of glycerol in 60 min/100 mg of total lipids) after stress. Insulin dose-dependently inhibited the lipolytic response to norepinephrine by up to 35% in adipocytes from control rats but had no effect on adipocytes from stressed rats. The liver glycogen content was unaltered by stress, but was lower in soleus muscle from stressed rats than in control rats (0.45 +/- 0.04 vs. 0.35 +/- 0.04 mg/100 mg of wet tissue). These results suggest that rats submitted to foot-shock stress develop hyperglycemia along with hyperinsulinemia as a consequence of insulin subsensitivity in adipose tissue, with no alteration in the pancreatic sensitivity to glucose. Foot-shock stress may therefore provide a useful short-term model of insulin subsensitivity.     

Glucose metabolism in isolated brown adipocytes under beta-adrenergic stimulation. Quantitative contribution of glucose to total thermogenesis.

To quantify the potential of brown adipose tissue as a target organ for glucose oxidation, O2 consumption and glucose metabolism in isolated rat brown adipocytes were measured in the presence and absence of insulin, by using the beta-agonists isoprenaline or Ro 16-8714 to stimulate thermogenesis. Basal metabolic rate (278 mumol of O2/h per g of lipid) was maximally stimulated with isoprenaline (20 nm) and Ro 16-8714 (20 microM) to 1633 and 1024 mumol of O2/h per g respectively, whereas insulin had no effect on O2 consumption. Total glucose uptake, derived from the sum of [U-14C]glucose incorporation into CO2 and total lipids and lactate release, was enhanced with insulin. Isoprenaline and Ro 16-8714 had no effect on insulin-induced glucose uptake, but promoted glucose oxidation while inhibiting insulin-dependent lipogenesis and lactate production. A maximal value for glucose oxidation was obtained under the combined action of Ro 16-8714 and insulin, which corresponded to an equivalent of 165 mumol of O2/h per g of lipid. This makes it clear that glucose is a minor substrate for isolated brown adipocytes, fuelling thermogenesis by a maximum of 16%.     

Stimulation of a glycosyl-phosphatidylinositol-specific phospholipase by insulin and the sulfonylurea, glimepiride, in rat adipocytes depends on increased glucose transport

Lipoprotein lipase (LPL) and glycolipid-anchored cAMP-binding ectoprotein (Gce1) are modified by glycosyl-phosphatidylinositol (GPI) in rat adipocytes, however, the linkage is potentially unstable. Incubation of the cells with either insulin (0.1-30 nM) or the sulfonylurea, glimepiride (0.5-20 microM), in the presence of glucose led to conversion of up to 35 and 20%, respectively, of the total amphiphilic LPL and Gce1 to their hydrophilic versions. Inositol- phosphate was retained in the residual protein-linked anchor structure. This suggests cleavage of the GPI anchors by an endogenous GPI-specific insulin- and glimepiride-inducible phospholipase (GPI-PL). Despite cleavage, hydrophilic LPL and Gce1 remained membrane associated and were released only if a competitor, e.g., inositol- (cyclic)monophosphate, had been added. Other constituents of the GPI anchor (glucosamine and mannose) were less efficient. This suggests peripheral interaction of lipolytically cleaved LPL and Gce1 with the adipocyte cell surface involving the terminal inositol- (cyclic)monophosphate epitope and presumably a receptor of the adipocyte plasma membrane. In rat adipocytes which were resistant toward glucose transport stimulation by insulin, the sensitivity and responsiveness of GPI-PL to stimulation by insulin was drastically reduced. In contrast, activation of both GPI-PL and glucose transport by the sulfonylurea, glimepiride, was not affected significantly. Inhibition of glucose transport or incubation of rat adipocytes in glucose-free medium completely abolished stimulation of GPI-PL by either insulin or glimepiride. The activation was partially restored by the addition of glucose or nonmetabolizable 2-deoxyglucose. These data suggest that increased glucose transport stimulates a GPI-PL in rat adipocytes.     

Mechanism of methaemoglobin reduction by human erythrocytes.

The effect of alterations to the insulin receptor on the insulin sensitivity of isolated adipocytes was studied. Receptor changes were induced by treatment of adipocytes with either phospholipase C or trypsin. After enzyme treatment, binding of insulin to insulin receptors and insulin-mediated glucose metabolism were examined. Exposure of adipocytes to phospholipase C (2 units/ml) significantly increased insulin binding to the cells, but destroyed the ability of the cells to oxidize glucose. After treatment with trypsin (500 micrograms/ml) for 5 min, insulin binding to the adipocytes was significantly increased. This was shown to be due to an increase in insulin-receptor affinity. Metabolic studies showed that trypsin treatment led to an increase in basal glucose transport but markedly decreased the response to insulin at all concentrations tested. Adipocytes treated with trypsin showed no significant difference in basal glucose oxidation rates when compared with controls, but were less sensitive to insulin at low insulin concentrations, and showed a decreased maximum response at high insulin concentrations. In conclusion, these findings indicate a dissociation between induced changes in binding of insulin to insulin receptors and subsequent hormone action. The importance of post-receptor events in the biological action of insulin is highlighted.     

胰岛素增强糖基化白蛋白对大鼠血管平滑肌细胞的促增殖作用

在糖尿病性大血管病变的发病过程中,高血糖以及晚期糖基化终末产物（advanced glycation end products,AGEs）、脂质异常和高胰岛素血症的相互作用较其单独作用可能更重要。本研究采用糖基化白蛋白（glycated serum albumin,GSA）模拟AGEs,观察胰岛素和GSA对大鼠血管平滑肌细胞（vascular smooth muscle cells,VSMCs）的增殖是否存在协同作用,并初步探讨其作用机制。采用组织贴块法分离培养大鼠VSMCs。经过或不经过各种丝裂原激活蛋白激酶（mitogen-activated protein kinases．MAPKs）抑制剂和氧自由基清除剂N-acetylcysteine（NAC）处理后,加入不同浓度的胰岛素、GSA或GSA＋胰岛素,用MTT法和细胞计数法检测VSMCs的增殖。采用Western blot检测p38MAPK和C-Jun N-terminal kinase1／2（JNK1／2）的磷酸化。结果显示,GSA和胰岛素联合作用促进p38MAPK的磷酸化,而对JNK1／2的磷酸化无明显影响。GSA和胰岛素均可促进VSMCs增殖,而且两者具有协同作用。p38MAPK抑制剂SB203580和NAC可以抑制GSA和胰岛素联合作用引起的VSMCs增殖。以上结果提示,胰岛素和GSA对促进VSMCs增殖有协同作用,这可能是通过氧化应激敏感的p38MAPK通路实现的。胰岛素和AGEs的协同作用在糖尿病性动脉粥样硬化和再狭窄的发病过程中可能起重要作用。     

Glucose‐dependent Insulin Modulation of Oscillatory Lipolysis in Perifused Rat Adipocytes

Objective: We showed glucose‐dependent lipolytic oscillations in adipocytes that are modulated by free fatty acids (FFAs). We hypothesized that the oscillations are driven by oscillatory glucose metabolism that leads to oscillatory formation of α‐glycerophosphate (α‐GP), oscillatory removal of long‐chain coenzyme A (LC‐CoA) by α‐GP to form triglycerides, and oscillatory relief of LC‐CoA inhibition of triglyceride lipases. This study examined the effect of insulin on this hypothesis. Research Methods and Procedures: Samples were collected every minute from perifused rat adipocytes during the basal state followed by insulin (±glucose) or isoproterenol (±insulin; n = 4 each). Results: Insulin caused a significant increase in glycerol release (18%), with a concomitant significant decrease in FFA release (38%). Without glucose, insulin had no effect on glycerol release while still decreasing FFA release (35%). Insulin (5 μU/mL) attenuated the response of lipolysis to isoproterenol (～3‐fold increase with isoproterenol vs. 2‐fold increase with insulin + isoproterenol). However, 1 mU/mL insulin amplified the lipolytic response (～5‐fold increase in glycerol release with insulin + isoproterenol), with a concomitant increase in FFA reesterification (no increase in FFA release compared with isoproterenol alone). Discussion: We interpret these results to be due to insulin's ability to increase glucose uptake and conversion to α‐GP, thus removing LC‐CoA inhibition of triglyceride lipases. While the physiological importance of lipolytic oscillations remains to be determined, we hypothesize that such an oscillation may play an important role in the delivery of FFAs to the liver, β cells, and other tissues.     

Effect of oral treatment with a new hypoglycemic agent, AS-6, on the metabolic activities of adipocytes in db/db mice: a comparative study

The mechanism of a new hypoglycemic agent, AS-6, was comparatively studied using the adipocytes from AS-6 treated and untreated genetically obese diabetic mice, db/db. the db/db mice were treated for 1 week with a diet admixture of AS-6 (0.1%). The treatment resulted in the following alterations in metabolic activities; AS-6 treatment increased 125I-insulin binding by 1.4-3.3 fold over the insulin range of 1-1000 microU/ml, the treatment increased the basal activities in 2-deoxyglucose uptake, and in CO2 generation and lipogenesis from U-(14C)-glucose compared with the db/db controls, the treatment partially restored insulin responsiveness in 2-DG uptake and CO2 generation, and 1 mU/ml of insulin greatly stimulated lipogenesis by 5.6 fold above the basal in the control adipocytes while AS-6 treatment changed the lipogenic response less stimulative to the insulin. The results suggest that AS-6 treatment significantly increases insulin binding to the adipocytes associating with an enhancement in glucose metabolism under basal and physiological concentrations of insulin.     

In vivo and in vitro effect of p-chlorophenoxyisobutyrate on insulin binding and glucose transport in isolated rat adipocytes

We studied the in vivo and in vitro effect of p-chlorophenoxyisobutyrate (CPIB) on insulin binding and glucose transport in isolated rat adipocytes. In the in vitro study, adipocytes were incubated with 1mM of CPIB for 2 h at 37 degrees C, pH 7.4, and then insulin binding (37 degrees C, 60 min) and 3-0-methylglucose transport (37 degrees C, 2s) were measured. Incubation with CPIB did not affect either insulin binding or glucose transport in the cells. The addition of insulin (10 ng/ml) with CPIB to the incubation media also did not affect the following insulin binding and glucose transport. In the in vivo study, rats were fed a high sucrose-diet containing 0.25% CPIB for 7 days. Serum cholesterol, plasma free fatty acid, and insulin levels were significantly decreased in the CPIB-treated rats. The treated rats demonstrated an almost 2 fold increased maximal binding capacity for insulin (189,000 sites/cell for treated vs 123,000 sites/cell for control cells). Basal glucose transport (glucose transport in the absence of insulin) significantly decreased in the CPIB-treated rats, although insulin-stimulated glucose transport was comparable in treated and control cells. Thus, CPIB might have no direct effect on glucose transport and insulin binding, as determined by the in vitro studies. Furthermore, a relatively short-term in vivo treatment with CPIB, such as 7 days, did not stimulate glucose transport.