1.Effect of cyclic mechanical stimulation on expression of connective tissue growth factor in MG63 osteoblast-like cells
Min YANG ; Liwei XIAO ; Lingyun HUANG ; Yiqun PENG ; Guoliang SUI ; Yuling HE ; Rongrong CUI ; Jiao HUANG ; Ying LU ; Eryuan LIAO
Chinese Journal of Endocrinology and Metabolism 2008;24(4):356-359
Objective To investigate cyclic mechanical stimulation on expression of connective tissue growth factor (CTGF) in osteoblast-like cells (MG63) and to explore the rote of MAPK involved in the process.Methods Expressions of CTGF protein and mRNA in MG63 cells were detected by Western blot and RT-PCR,respectively. Phosphorylation levels of p38, ERK, JNK were examined by Western blot. Results Cyclic mechanical stimulation upregulated expressions of CTGF protein and mRNA. The levels reached a maximal response of 2-3 fold after 3-6 h. ERK and JNK signal pathways were activated by cyclic mechanical stimulation, the phosphorylated proteins increased within 10 min of stretch, phosphorylated ERK reached maximal levels by 60 min of stretch, phosphorylated JNK reached maximal levels by 15-30 min of stretch, but not for p38 signal pathway.Only the inhibitior of JNK signal pathway (SP600125) markedly suppressed stretch-induced CTGF expression,meanwhile the inhibitors of ERK (PD98059) and p38 (SB203580) did not show such effect. Conclusion Cyclic mechanical stimulation upregulates CTGF expression via JNK-dependent pathway in MG63 cells.
2.Some issues in the evaluation of insulin resistance in experimental research
Chinese Journal of Endocrinology and Metabolism 2008;24(4):354-355
Some issues in the evaluation of insulin resistance in experimental research were discussed.Except glucose clamp test, other methods used in animal experiments are not appropriate now.
3.Effects of fenofibrate and pioglitazone on expressions of intracellular signaling molecules in pancreatic islet of high-fat diet-fed rats
Ting FENG ; Bo YANG ; Haoming TIAN
Chinese Journal of Endocrinology and Metabolism 2008;24(4):416-419
Objective To observe the effects of fenofibrate and pioglitazone on the expressions of PPAR- α, PPAR-γ, and intracellular signaling molecules in pancreatic islets of obese rats induced by high-fat diets. Methods SD obese rat models were established with high-fat diet, and 40 male rats were assigned to 4 groups including high-fat diet (HF group), high-fat diet with fenofibrate (FF group), pioglitazone (FP group) treatment, and control rats with normal diet (NC group). After 8 weeks intervention, immunohistochemistry was performed to evaluate the expressions of various proteins in islets; At the same time, islets mass were scored in tissue slides. Results Islets mass enlarged in HF group. The compositions of islet cells were the same as the control. The expression of insulin was lower in HF group than the control, but after using pioglitazone, less islets mass and more insulin expression were found in FP group. Compared with the control group, expressions of PPAR-α, PPAR-γ protein were reduced in HF group, and the expression of PPAR-α protein increased in FF group, and the expression of PPAR-γ protein was increased in FP group. The levels of NF-кB, p38 mitogen-activated protein kinase (MAPK), ERK1 proteins increased significantly in HF group, the expressions of NF-кB, p38 MAPK decreased in FF and FP groups, and the level of ERK1 decreased only in FP group, the protein level of I-кB showed no difference among control, HF group, and FF groups. Conclusion Fenofibrate and pioglitazone may partially protect islet cells function and improve survival by correcting the disturbance of intracellular signaling molecules.
4.Clinical characteristics of women with polycystic ovary syndrome without detection of polycystic ovary
Yuhua SHI ; Yan SHENG ; Zijiang CHEN ; Peng ZHANG ; Li YOU
Chinese Journal of Endocrinology and Metabolism 2008;24(4):414-415
876 women with polycystic ovary syndrome (PCOS) were collected from Sep 2004 to Oct 2006. Among them 800 patients with polycystic ovary ultrasound image belonged to group A; the other 76 women without polyeystic ovary ultrasound image belonged to group B. As compared with group A, group B showed significantly higher hirsutism scores, serum testosterone, cholesterol, and lower density lipoprotein. Significantly higher prevalences of diabetes mellitus and hypertension appeared in the first degree relatives in group B than in group A.
5.Analysis of glucose dysbolism in patients with ectopic ACTH syndrome
Lei ZHAO ; Yiming MU ; Jingtao DOU ; Juming LU ; Changyu PAN
Chinese Journal of Endocrinology and Metabolism 2008;24(4):410-411
The characteristics of glucose dysbolism in ectopic ACTH syndrome (EAS) were investigated by analysing the clinical data of 117 patients with Cushing syndrome (CS). The patients with CS were divided into 3 groups : EAS group (n = 9) , Cushing's disease (CD) group (n = 67) and adrenocortical adenoma (AA) group (n =41). Retrospective analysis of the data covered the prevalence of secondary diabetes, blood glucose, HbAlc, blood potassium, and blood ACTH and 24 h urinary-free cortisol (UFC) levels. Compared with CD and AA groups, the prevalence of secondary diabetes and blood glucose level were higher in EAS group, while HbAlc level was lower. Blood glucose level in patients with ectopic ACTH syndrome decreased to normal after tumor removal.
6.Effect of JNK pathway, endoplasmic reticulum stress and oxidative stress on pancreatic islet β cell function
Zhiqiang HOU ; Hongliang LI ; Guangwei LI
Chinese Journal of Endocrinology and Metabolism 2008;24(3):348-350
Though the mechanisms involved in the induction of pancreatic islet β cell dysfunction and apoptosis under diabetes conditions are still not clear, previous studies have shown that triggered or aggravated endoplasmic reticulum stress and oxidative stress play essential roles in impairment of β cell functions, especially the JNK pathway which can be activated by both of them.
7.Compensatory mechanisms of islet β cells In early stage of insulin resistance
Ying DAI ; Wei CUI ; Bingyin SHI
Chinese Journal of Endocrinology and Metabolism 2008;24(3):345-347
The response of normal islet β cells to insulin resistance is compensatory insulin hypersecretion in order to maintain normoglycemia. The mechanisms involved in the compensation process including the expansion of β cell mass and enhanced β cell performance via various molecular cascades, signaling pathway sand their interactions have been extensively investigated in recent years.
8.Clinical significance of lowering the cut-point of impaired fasting glucose: in view of the extent and severity of angiographic coronary artery disease and the cardiovascular risk factors
Haiyan SU ; Changyu PAN ; Min LIU ; Mengmeng JIN
Chinese Journal of Endocrinology and Metabolism 2008;24(3):261-264
Objective To evaluate the rationale of lowering the cutoff value of impaired fasting glucose(IFG)by studying the extent and severity of angiographic coronary artery disease(CAD)and the cardiovascular risk factors in subjects with different fasting plasma glucose(FPG)levels. Methods A total of 911 consecutive patients who had undergone coronary angiography were selected according to inclusion criteria. The subjects were studied in view of the extent and severity of angiographic CAD and the cardiovascular risk factors with different FPG levels. Results (1) Compared with the group of FPG<5.6mmol/L, the numbers of diseased vessels in the group with FPG 5.6-6.0mmol/L were significantly increased(P<0.05)after adjustment of age, sex and other influencing factors; the group with FPG 6.1-6.9mmol/L had both raised number of diseased vessels and the CAD Gensini cumulative index(P<0.01). (2) The prevalences of overweight, hypertension, hypertriglyceridemia, metabolic syndrome were progressively increasing with graded FPG levels. The prevalence of hypertriglyceridemia was significantly increased with FPG level at 5.0-5.6mmol/L(P<0.05),and the prevalences of metabolic syndrome and other components were significantly elevated with FPG level at 5.6-6.0mmol/L(P<0.05). Conclusion (1) The extent and severity of angiographic CAD were increased with increased FPG even in prediabetic period. The risk of angiographic CAD became increased significantly with FPG at 5.6-6.0mmol/L level. (2) The cardiovascular disease(CVD)risk was also increased with increasing FPG even in prediabetic period. The phenomenon of clustering of CVD risk factors was found at FPG 5.6mmol/L.
9.Assay of growth hormone receptor gene mutations in children with idiopathic short stature
Xingxing ZHANG ; Zhuwen YI ; Xiuying WANG ; Xiaojie HE ; Qingnan HE
Chinese Journal of Endocrinology and Metabolism 2008;24(3):254-255
A homozygous A to G transition (AGT to GGT) in codon 16 of growth hormone receptor (GHR) gene was found in one patient with idiopathic short stature(ISS), resulting in an amino acid change(Ser16Gly). This may be a novel GHR gene mutation; and another novel Arg43Gln GHR gene polymorphism was found in Chinese people.
10.Effect of the unbalanced expressions of VEGF and PEDF on diabetic nephropathy
Jing LI ; Zhenjin LI ; Jing CUI ; Shue WANG ; Yan BAO ; Yingchun YE
Chinese Journal of Endocrinology and Metabolism 2009;25(2):203-205
The expressions of vascular endothelial growth factor(VEGF)and pigment epithelium derived factor(PEDF)in the tubulointerstitium were determined by immunohistochemistry in the streptozotoein-induced diahetic rats.The mRNA expressions of VEGF and PEDF in normal rat kidney (NRK) were measured by using RT-PCR under different high glucose conditions.The results showed that VEGF expression increased and PEDF expression decreased in the kidney tissue of the streptozotocin-induced diabetic rats.Hiish glucose increased VEGF expression and decreased PEDF expression in N RK cells in a time-and dose-dependent manner.The unbalanced expressions of VEGF and PEDF may play an important role in the occurrence and progression of diabetic nephropathy.