Iranian Journal of

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Background: Urtica dioica, or the stinging nettle, is recommended by ancient medical texts for the treatment of high blood sugar.
Methods: We set up a perifusion system, in which an exact number of islets of Langerhans were exposed to an active component of the leaf extract of Urtica dioica, obtained by TLC. The active component was then injected into the peritoneum of both normal and diabetic rats to evaluate response in vivo.
Results: There was a marked increase in insulin secretion in vitro, as determined by ELISA. In vivo, there was an increase in blood insulin content following intraperitoneal injection. The increase in serum insulin observed at 60 minutes was associated with a decrease in blood glucose, checked several times during the observation period. Maximum insulin release over 120 minutes was equal to five times the baseline value. The decrease in blood sugar correlated with both the timing and magnitude of insulin release.
Conclusion: Notwithstanding the magnitude of the changes observed, the results obtained in normal and diabetic rats were similar.

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Background: Studies of the metabolic effects of Ramadan fasting on patients with type 2 diabetes mellitus are inconclusive.
Methods: Fifty-seven volunteers with type 2 diabetes underwent anthropometric and biochemical evaluation before and on the 14th and 28th days of Ramadan. Biochemical markers were measured by standard laboratory methods. Anthropometric measurements followed WHO criteria. Statistical analysis was by ANOVA for repeated measurements and Friedman’s two-way ANOVA, using SPSSv6 software.
Results: Daily cholesterol intake increased in all subjects (p<0.03). Body mass index increased (p<0.03) in women, but body mass index (BMI) and waist-to-hip ratio both decreased (p<0.01) in men. Blood pressure, fasting blood glucose and serum fructosamine did not change during the study. Plasma insulin (p<0.05), C-peptide (p<0.01) and insulin resistance (p<0.01) decreased only in men. Total and LDL cholesterol increased significantly in all subjects during the study.
Conclusion: Ramadan fasting does not alter carbohydrate metabolism or tissue insulin sensitivity in type 2 diabetes patients, given appropriate dietary education and rescheduling of oral hypoglycaemic medication. Lipid profile is unfavourably altered due to changes in both diet and biochemical response to starvation. Anthropometric indices improve in men but not women, possibly because of reduced physical activity in the latter.

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Objective: To compare the effect on insulin absorption intra-nasally of Acanthophyllum squarrosum (ASQ) compared with Acanthophyllum saponaria (ASA) and sodium cholate (NAC), which have proven pro-absorptive effects.
Methods: The formulation used in this study contained 2IU insulin (per rat), 1% carboxymethylcellulose (CMC) and a pro-absorptive agent at the same concentration. We assessed the hypoglycaemic effect of each formulation in 5 rats in the fasting state.
Results: There was no significant difference in the pro-absorptive effects of ASQ, ASA, and NAC. Blood glucose levels 2 hours after administration of insulin, given as a percentage of baseline glucose concentration, were as follows for the three formulations used: ASQ: 36.78±11.06%, ASA: 27.46±2.39%, and NAC: 39.94±14.93%. Conclusion: Acanthophyllum squarrosum has a significant pro-absorptive effect, comparable to that to Acanthophyllum saponaria.

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Background: Cardiac X Syndrome is the occurrence of angina pectoris in spite of a normal coronary angiogram, probably due to a disorder of the cardiac sensory nervous system (pain perception). The insulin resistance (metabolic X) syndrome is an important determinant of coronary artery disease. There is a dearth of research on the association between insulin resistance and cardiac X syndrome. We compared the hormonal status of three groups of postmenopausal women: those with cardiac X syndrome, those with coronary artery disease, and healthy controls.
Methods: 149 postmenopausal women (age range 48-58 years), matched for duration of menopause, were recruited for this study. Gonadotrophin and fasting insulin levels as well as blood pressure and body mass index were measured in all three groups.
Results: LH, FSH, oestradiol and progesterone levels were similar in all three groups. Women in the first two groups (that is, those with angina pectoris regardless of the result of coronary angiography) had a significantly higher BMI than controls. Fasting insulin levels were significantly higher in the first two groups compared with controls (p<0.01). There was no difference in fasting insulin level between the normal and abnormal angiography groups. There was no significant correlation between fasting insulin and any of the other variables, even though the association between fasting insulin and BMI in the abnormal angiography-confirmed CAD group very nearly approached statistical significance (p=0.059).
Conclusion: Women with angina pectoris, regardless of the outcome of coronary angiography, have hyperinsulinism and a higher BMI than controls. It seems that hyperinsulinism is the fundamental mechanism by which both the cardiac X and metabolic X syndromes occur. Further research is needed to elucidate this matter.

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Insulin resistant states are emerging rapidly and lots of efforts have gone into understanding their pathogenesis and major metabolic consequences. Hypertriglyceridemia, a major complication of this metabolic syndrome, seems to be caused by overproduction of lipoproteins (LPs) containing apo B that are rich in triglycerides. Some in vitro and in vivo models have been introduced so as to understand mechanisms governing lipid metabolism in insulin resistance states. Human and animal studies have suggested a key role for overproduction of VLDL in hypertriglyceridemia and dyslipidemic states. Recently, we have employed a diet-induced animal model of insulin resistance (hamster fed with fructose) in our laboratory in order to examine the relationship among development of insulin resistant state, impaired metabolism of LPs and overproduction of LPs containing apo B. These experiments have indicated that insulin resistant states occur along with overproduction of VLDL containing apoB105 from liver and enteral LPs rich in apo B 48. In insulin resistant states, decreased metabolic signaling to liver and intestine seems to play a critical role in overproduction of LPs. We have also been recognized a number of intracellular factors which may regulate VLDL production. This article reviews recent advances in the area the hypothesis indicating that a complex interaction exist between increased free fatty acids flow from peripheral tissues to the liver and intestine (caused by hyperinsulinemia) and prolonged lipogenesis has also been expounded.

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Background: Insulin dependant Diabetes Mellitus (IDDM) is associated with a reduction in production or secretion of insulin from pancreatic Islets. On the other hand increase in insulin secretion will result in destruction of islets that will lead to Diabetes .Therefore the factors that could regulate secretion will prevent the onset of diabetes . Glucose metabolism that commences with the glucokinase action is closely related to insulin secretion. The aim of this study is to survey the effect of eat ions Zn2+, V5+ and W5+ on insulin secretion and on the key enzyme, glucokinase, which is known to play an important role in insulin secretion .
Methods: 20 single islets were seprated from pancreatic tissues of each normal and diabetic rats and placed in tubes containing perfusion medium . Method ions with different concentrations/ and controls were provided with each set of experiment . Insulin secretion were determined using IDMA method. Glucokinaes activity in homogenate supernatant of normal and diabetic rats was assayed by spectropho to metric methods.
Results: the level of insulin concernlyation was shown to increase with vandate and tungsten treatment in normal and diabetic rats / and decreased by zinc .The effect of zinc on glucokinase activity was similarly reducing . Tungsten caused an increase in glucokinase activity (p<.001) while vandate showed no effect on the activity of enzyme .
Conclusion: The inhibitory effect of zinc on insulin secretion and the enhancing effect of tungsten correlate closely with their effect on glucokinase activity. There for the effect in insulin secretion could be assumed to be via glucokinase activation or inhibition . The effect of vandate on insulin secretion my be through other mechanisms which is not yet clarified.

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Background: Polycystic ovary syndrome (PCOS) which is characterized by menstrual irregularities (due to chronic anovulation) and hyperandrogenism is one of the most common endocrine disorders of women at reproductive age. The precise cause of PCOS is unknown, but it seems that several factors may have role in its pathogenesis. Insulin resistance and impaired insulin secretion are common findings in PCOS patients. Approximately 30 – 40 % of women with PCOS have impaired glucose tolerance or type 2 DM. According to my knowledge, there is no published study about prevalence of IGT and type 2 Diabetes Mellitus (type 2 DM) in Iranian women with PCOS. The aim of this prospective, controlled study was to determine the prevalence of abnormal glucose metabolism in women from north west part of the country.
Methods: 302 PCOS women and 116 normal women as a control group were prospectively studied. The diagnosis of PCOS was made based upon the presence of chronic anovulation and hyperandrogenemia. Other causes of hyperandrogenism were excluded by appropriate clinical and laboratory evaluations. None of the patients were known diabetics prior to study. In all patients with PCOS and control women appropriate medical history was taken and physical examination was done. Blood pressure, body weight, height, BMI, waist / hip ratio, score of hirsutism and other signs of androgen excess were determined. Serum concentrations of total testosterone and DHEA–S were measured by RIA methods in both patients and control group. Standard Oral Glucose Tolerance Test (OGTT) with 75 grams oral glucose was performed between 8 -9 AM after an overnight fast of 10 – 12 hours. Fasting and 2 – hour post - glucose plasma sugars were measured by glucose oxidase method. Results: Results of OGTT were interpreted according to WHO criteria. Mean age and mean BMI were similar in both patients and controls. Serum levels of total testosterone and DHEA – S were significantly higher in PCOS women in comparison with controls. 65% of patients and 68% of controls had BMI of ≥ 25 kg / m2. 55% of PCOS women and 51.6% of control women were obese (BMI ≥ 27kg/m2). 96 (31.7%) of PCOS women had impaired glucose tolerance (IGT) and 27 (8.9%) were diabetics. The prevalence of IGT and diabetes in controls were 14.6% and 5.1% respectively. In non-obese PCOS women the prevalence of IGT and DM were 17.2% and 3.6% respectively, while only 8.9% of control women had IGT and 1.7% were diabetics. Finally, 44.1% of obese PCOS women were glucose intolerant and 13.5% had diabetes mellitus in comparison with 20% and 10% of controls. Conclusion: It is concluded that the prevalence of IGT and DM in both obese and non–obese PCOS women were significantly higher than in control women. Screening of all PCOS women for IGT and DM is highly recommended.

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Background: Increased echogenicity of pancreas, due to hemosiderosis, is a frequent finding in  - thalassemic paitents. Hemosiderosis also leads to  - cell dysfunction. So diabetes and glucose intolerance are common consequences of hemosiderosis. The aim of this study was to investigate the association of increased pancreas echogenicity (IPE) with insulin sensitivity in  - thalassemic children aged 10-20 years.
Methods: After exclusion of thalassemic paitents with diabetes or familial history of diabetes, pancreas ultrasonography was performed in 42 -thalassemic children and they were divided into 2 groups with normal (21) and increased (21) pancreas echogenicity. Serum ferritin was measured, as well as serum insulin and glucose values, during an OGTT, at 0, 30, 60 and 120 minutes. A control group was selected randomly (n= 23). Insulin Sensitivity Index and Fasting Glucose/Insulin Ratio were calculated and the data were analysed using t-test and ANOVA statistical methods.
Results: Serum feritin differed significantly between 2 groups of thalassemic paitents (P<0.005), but the insulin and glucose values were not significantly different among studied population (P>0.05). Serum feritin was inversely correllated with ISI in patients IPE and 28.6% of them had IFG, as compared to patients with normal echogenicity (P<0.05).
Conclusion : Regarding the detection of all IFG cases among thalassemic paitents with IPE and the relation of feritin with ISI in this group, pancreas ultrasonography may be used to investigate the early stages of diabetes in these patients. however after conducting further studies with larger sample size and on older paitents are recommended.

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Background: The precise mechanisms of vascular diseases in insulin dependent diabetes mellitus (IDDM) are not clearly understood. There are evidences of alteration in mechanisms involved in regulating vascular tone including increased ACE activity in some tissues. To investigate the effect of insulin treatment on these changes this study was performed.
Methods: Three groups of 8 male Sprauge Dawely rats including control (C) and two diabetic groups (D, IT) were used in this study. Diabetes was induced by injection of 60 mg/kg STZ ip. After induction of diabetes IT group were treated with insulin (10 units/kg/day s.c.) for four weeks. The control group and the untreated diabetic group were treated with the same amount of Saline and for the same time. ACE activity was determined by HPLC method.
Results: 4 weeks after induction of diabetes, SBP and ACE activity in serum, lung, heart and aorta increased in D group compared to control rats. Insulin treatment reversed these changes to normal values in IT group.
Conclusion: It is concluded that increased ACE activity could contribute to the development of diabetic vasculopathy and ACE reducing activity of insulin may be partially involved in decrease of cardiovascular complications in diabetes.

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Background: Leptin is an adipocyte- derived hormone that plays an important role in the pathogenesis of obesity. Obesity is associated with insulin resistance and hyperinsulinemia. Insulin resistance is one of the factors which have been suggested to affect leptin serum levels. There are few studies evaluating the relation between leptin level and insulin resistance in childhood and adolescence obesity. The aim of the present study is to investigate this relationship in Iranian obese children. Methods: We screened 13089 primary school students aged 7-12 years. Children were divided to overweight and normal based on the recently published National Center for Health Statistics growth charts. The number of children which were overweight was 498, of whom 347 subjects particiated in the study. Fasting blood glucose, insulin and leptin levels were measured and homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR) and fasting glucose to insulin ratio (FGIR) were calculated and compared between two groups. Results: Serum leptin levels were significantly higher in overweight compared to normal group. (11.58±8.1 and 8.1±5.2 respectively p<0.05). Before adjustment for BMI, there was a significant correlation between leptin and fasting insulin, HOMA –IR index and FGIR. (r=0.1, p< 0.05, r=0.1 , p<0.01, r=0.07, p<0.05 respectively). After adjustment for BMI, no significant correlation was found (r=0.097, p=0.20). Conclusion: The relation between leptin and insulin resistance was weak and disappeared after adjustment for BMI. It seems that many other factors including BMI and total fat amount may affect this relationship. Further studies in this field are required.

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Background: All contemporary methods of insulin administration are non-physiological. Insulin is not absorbed from the gastrointestinal tract because of its peptide nature. The aim of the present study was to examine the absorption of oral insulin from gastrointestinal tract, using novel oral formulation- adding a delivery agent superporouse hydrogel (SPH) and SPH composite (SPHC) in combination with insulin.
Methods: Capsules containing insulin and SPH &SPHC were administered orally, to 15 non-diabetic subjects in order to assess its biological effects and safety. Plasma glucose, insulin and c – peptide serum levels were determined, at timed intervals up to 4 h.
Results: In the present study, we showed that AUC of exogenous insulin in polymer -insulin group was higher than sub-cutaneous regular insulin group. It means that addition of SPHC polymer caused increase in insulin absorbtion.In addition, Insulin Tmax in polymer group was longer than sub-cotaneaus insulin group. Blood glucose AUC in sub-cotaneaus group was higher than polymer group.AUC C-peptide serum level in polymer group was higher than sub-cutaneous group.
Conclusions: Insulin in combination with a novel delivery agent, SPH and SPHC, given orally is absorbed through the GI tract in a biologically active form. This was demonstrated by suppression of endogenous insulin secretion.

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Background: The determination of insulin receptors on RBC membrane is a suitable tool for the study of these receptors in diabetes and its related complications. The common methods for the study is the biopsy of fat or muscular tissues, cell culture or a preparation of certain amount of monocytes which is associated with some difficulties. Present study utilizes RBC's for this purpose.
Methods: Certain amount of RBCs were exposed to a known amount of labeled Insulin and varying concentration of unlabelled Insulin. The competitive effect of Insulin replacement was determined by the measurement of residual receptor radioactivity. This study was carried out in three groups of healthy, poor controlled and good controlled diabetics.
Results: There were significant differences between the normal and poor controlled diabetics (P=0.017). In addition differences in receptor binding was obtained between good controlled diabetics and normal which were not significant (P=0.09). All changes were inversely proportional to the HbA1C of specimen. Using Scat chard plots the number of receptors in each group, normal, poor controlled and good controlled were determined to be 1820 (± 72.8), 1026 (±40.4) and 1230 (± 49.2) respectively.
Conclusion: Considering the above results, it could be seen that the evaluation of the number of receptors in RBC could be a suitable tool for studying the state of insulin receptor in both physiological and pathological conditions.

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Background: The aim of this study was to compare time action profile of regular human Insulin produced by Exir pharmaceutical Co. and Actrapid® HM produced by Novo Nordisk with euglycemic clamp technique for the first time in Iran.
Methods: Euglycemic glucose clamps were performed with two Insulin brands in a single-center, randomized, double-blind, and crossover study on 6 healthy male volunteers. Glucose disposal kinetics including metabolic clearance rate of glucose (MCRg) and metabolic clearance rate of insulin (MCRi) were determined during a 2-h predetermined intravenous Insulin infusion while blood glucose levels were maintained steady using variable continues intravenous glucose infusions based on method of De Fronzo.
Results: There were no differences in glucose kinetics or time action profile with respect to glucose infusion rates (688.4 vs. 664.6 mg/kg per 120min), MCRg (0.63±0.19 vs. 0.62±0.25 ml/kg), and MCRi(110 % vs110%) between Exir and Novo Nordisk regular human Insulin preparations. Serum insulin levels increased and serum C-peptide levels decreased with both exogenous Insulin infusions which were statistically the same for both preparations.
Conclusion: Time action profile and bioavailability of regular human insulin produced by Exir Pharmaceutical Corporation is comparable with commonly used Novo Nordisk preparation demonstrated by 2 hour euglycemic clamp study.

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Background: All contemporary methods of insulin administration are non-physiological. The euglycemia that is achieved in at the expense of the adverse effects of systemic hyper-insulinemia, emphasize the importance of devising methods to deliver insulin physiologically and directly into the portal circulation. The aim of the present study was to evaluate the oral absorption of insulin from gastrointestinal tract, using novel oral drug delivery system delivery based on superporouse hydrogel (SPH) and SPH composite (SPHC) in combination with insulin.
Methods: This study has been done based on interventional clinical trial in healthy volunteers. Capsules containing insulin and SPH &SPHC in various combination were administered orally, to 15 non-diabetics subjects in order to assess this biological effects and safety. Serum glucose, insulin and C - peptide levels were determined, at predetermined timed intervals up to 4 h.
Results: An increase in serum insulin level was demonstrated in all subjects that used polymer plus insulin. The nadir of serum glucose level appeared after 60 - 120 min following the ingestion of polymer plus insulin. Serum C - peptide levels were suppressed while exogenous insulin was absorbed at the same time. No adverse effects were detected during the trial and several weeks following the trial using SPH based drug delivery system.
Conclusions: Insulin in combination with novel delivery agents, SPH & SPHC, given orally was partially absorbed through the GI tract in a biologically active form. This was demonstrated by serum glucose lowering effect of the delivery system as well as a suppression of plasma C-peptide which also represented a decrease in endogenous insulin secretion.

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Background: Glucokinase serves as a glucose sensor in pancreatic β-cells and plays a key role in glucose homeostasis and glucose-stimulated insulin secretion (GSIS). In the present study we examined the effect of glucosamine, a glucokinase inhibitor, on the pancreatic glucokinase and hexokinase activities and on insulin secretion from freshly rat pancreatic islets of Langerhans. Insulin concentration was measured by rat insulin ELISA kit. Methods: The pancreatic islets from normal and type 2 diabetic (nSTZ) rats were isolated by collagenase digestion method. Glucose phosphorylation was quantitated by measuring the rate of glucose-6-phosphate formation in the fluorometric assay. Insulin secretion from hand-picked islets was evaluated in static incubation system. Insulin concentration was measured by rat insulin ELISA kit. Results: Our findings demonstrate that glucosamine in a dose dependent manner, reduced glucokinase activity in islet extract, but had no effect on hexokinase activity. The glucose-stimulated insulin secretion, was inhibited by glucosamine but it had no effect on the basal insulin secretion. In diabetic rats glucokinase was decreased while the basal insulin secretion and the activity of hexokinase were higher than normals. Conclusion: Based on results obtained from the present study, the assumption could be made that the decrease in the activity of glucokinase of pancreatic islets could be related to the impaired glucose stimulated insulin secretion. The increase in basal insulin secretion of diabetic rats may be due to an increase in pancreatic hexokinase activity.

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Background: Obesity is an escalating public health problem. It is a major risk factor for atherosclerosis, hypertension, and type 2 diabetes. Since circulating levels of the adipocytokins are associated with obesity and dyslipidemia, we investigated the relationship of plasma adipocytokine concentrations with VLDL apolipoprotein B (apoB)-100 kinetics in men.
Methods: Plasma adiponectin, leptin, resistin, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) concentrations were measured using enzyme immunoassays and insulin resistance by homeostasis model assessment (HOMA) score in 41 men with BMI of 22–35 kg/m2. VLDL apoB kinetics were determined using an intravenous infusion of 1-[13C]leucine, gas chromatography–mass spectrometry, and compartmental modeling. Visceral and subcutaneous adipose tissue mass (ATM) were determined using magnetic resonance imaging, and total ATM was measured by bioelectrical impedance.
Results: In univariate regression, plasma adiponectin and leptin concentrations were inversely and directly associated, respectively, with plasma triglyceride and HOMA score. Conversely, adiponectin and leptin were directly and inversely correlated, respectively, with VLDL apoB catabolism and HDL cholesterol concentration (P < 0.05). Resistin, IL-6, and TNF-α were not significantly associated with any of these variables. In multivariate regression, adiponectin was the most significant predictor of VLDL apoB catabolism (P= 0.001) and, together with visceral ATM, was an independent predictor of plasma VLDL apoB concentration (P = 0.015) HOMA score was the most significant predictor of VLDL apoB hepatic secretion (P= 0.049). Leptin was not an independent predictor of VLDL apoB kinetics.
Conclusion: Plasma VLDL apoB kinetics may be differentially controlled by adiponectin and insulin resistance, with adiponectin regulating catabolism and insulin resistance regulating hepatic secretion in men. But leptin, resistin, IL-6, and TNF-α do not have a significant effect in regulating apoB kinetics.

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Background: Although there is increasing evidences that vitamin D is related to the occurrence of diabetes mellitus, its relation to glucose metabolism in pregnancy is not well studied. This study investigated 25-hydroxyvitamin D deficiency status in GDM pregnant women.
Methods: As a cross sectional study we recruited 741 pregnant women referred to five university educating hospital clinics. The universal screening was performed with a GCT-50g and those with plasma glucose level ≥130mg/dl, were diagnosed as GDM, if they had an impaired GTT-100g based on Carpenter and Coustan criteria. The levels of insulin was studied during OGTT-100g. Serum concentrations of 25-hydroxy vitamin D was measured too.
Results: Univeriate analysis revealed that 25 (OH) vit D concentrations were positively correlated with HOMA and ISOGTT index. Subjects with hypovitaminosis D (<12.5nmol/dl) had greater prevalence of GDM than others.
Conclusion: The results reveal a positive association between 25(OH) vit D concentrations and insulin sensitivity. Vit D deficiency is more prevalent in patients with GDM than normal pregnant women, So vit D supplementation may control glucose levels and improves outcome of pregnancy.

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Background: Regarding the adverse effect of stress on glycemic control in type 2 diabetic patients, the present study investigates the function of Glibenclamide on insulin release from β cells of rat pancreatic islets, subsequent to chronic psychological stress exposure.
Methods: In this study 30 male Wistar rats were divided into equal groups of control and experiment (5 groups). Four different restraint stressors with random sequence were used 1h twice daily for 15 and 30 days. 24 hours after the last stress session, static insulin secretion from isolated pancreatic islets of each animal were evaluated in the presence of 5.6, 8.3 and 16.7 mM glucose. Also insulin release in response to 5.6 mM glucose in the presence of 10 μM Glibenclamide was evaluated.
Results: The insulin release from isolated islets of the stress experienced animals was significantly increased only on the 30th day as compared to the control animals. In the experiment group, insulin release from the islets in the presence of 5.6 mM glucose alone was significantly increased on the 15th and 30th days as compared to the first day. However, in the control group there was no significant increase in insulin release at the similar conditions. In contrast to the control group, insulin release in response to 5.6 mM glucose in the presence of 10 μM Glibenclamide revealed no significant difference in the experiment group on the 1st 15th and 30th days as compared to the insulin release in the presence of 5.6 mM glucose alone. Insulin release from the isolated islets exposed to 5.6 mM glucose in the presence of 10 μM Glibenclamide, on different experimental days was not significantly different between the control and experiment groups.
Conclusion: According to the results of this study, it appears that chronic psychological stress decreases the responsiveness of pancreatic β cells to Glibenclamide, subsequently could prevent the augmentation of insulin release induced by the drug. This finding is worthy to consider in metabolic control of diabetic patients whom consume the agent.

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Background: Gestational diabetes mellitus is a common metabolic disorder in pregnancy. Low levels of sex hormone–binding globulin level (SHBG) is associated with increased insulin resistance and hyperinsulinemia. The aim of this study was comparison of SHBG levels between gestational diabetic pregnant women and normal ones.
Methods: Serum SHBG concentration were measured in 38 women with gestational diabetes and in 143 women with normal pregnancy. The levels of Insulin, C-peptide and testosterone were measured and Insulin resistance was estimated via HOMA Index. Insulin sensitivity was estimated via QUIKE Index.
Results: Serum SHBG concentrations was significantly lower in the diabetic group (P=0.015). In a logistic regression model after adjustment of age, body mass index (BMI) and number of gravid, lower than 25 percentile of SHBG was independently effective in prediction of gestational diabetes mellitus.
Conclusion: SHBG concentrations are lower in gestational diabetic pregnant women and low levels account as a predictor of gestational diabetes mellitus.

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Background: Sulfonylurea agents such as Glibenclamide (Glyburide) have been widely prescribe in treatment of type 2 diabetic patients for decades, but controversy remains about their precise mechanism of action. On the other hand, glucokinase serves as a glucose sensor in pancreatic β-cells and plays a key role in the regulation of insulin secretion and glucose homeostasis. The aim of the present study was to evaluate the effect of Glibenclamide on insulin secretion and glucokinase activity in the rat isolated pancreatic islets of Langerhans.
Methods: The islets from normal and type 2 diabetic rats were isolated by collagenase digestion method. Glucokinase activity was measured via determination the rate of glucose-6-phosphate formation in the fluorometric assay. Insulin secretion from hand-picked islets was evaluated by static incubation technique. Insulin concentration was measured by rat insulin ELISA kit.
Results: Our findings obtained from incubation of Glybenclamide with pancreatic islets revealed that this agent increases basal insulin secretion (at 2.8 mM glucose) in both normal and diabetic rats as compared it with control islet (without drug). However, the increase of insulin secretion in response to 16.7 mM glucose was not significant. On the other hand, Glybenclamide had no activating and/or inhibiting effect on pancreatic glucokinase activity in both diabetic and normal Rats. But reduced activity of this enzyme in diabetic rats was significant in comparison with normal.
Conclusion: These data show that increasing effect of Glybenclamide on insulin secretion is through a mechanism other than affecting Glucose Mediated Insulin Release. Moreover, the regulation of pancreatic glucokinase does not depend on glybenclamid.