Polycystic ovary syndrome is associated with genetic polymorphism in the insulin signaling gene IRS-1 but not ENPP1 in a Japanese population

Recent studies indicate that insulin resistance resulting from altered post-receptor signaling is associated with polycystic ovary syndrome (PCOS). We hypothesized that insulin receptor substrate-1 (IRS-1) Gly972Arg polymorphism and/or ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) Lys121Gln polymorphism predisposes women to PCOS and that these polymorphisms also affect anthropometric variables, glucose metabolism and androgen synthesis. To test those ideas, we studied the genotypes, indexes of insulin resistance, and hormone profiles in 123 Japanese women with PCOS and 380 healthy Japanese controls. We found that there were significantly more IRS-1 972Arg carriers among the PCOS patients than among the healthy controls (10.6% vs. 4.8%, p=0.029), which is consistent with our finding that women carrying the IRS-1 972Arg allele had a significantly increased risk of developing PCOS (odds ratio: 3.31, 95% confidence interval: 1.49-7.35). By contrast, the ENPP1 Lys121Arg polymorphism was distributed equally among PCOS patients and controls. In addition, neither of these polymorphisms studied affected the anthropometric variables, metabolic parameters or androgen levels of women with PCOS. We conclude that the IRS-1 Gly972Arg polymorphism is associated with PCOS in the Japanese population.     

Androgen levels and metabolic parameters are associated with a genetic variant of F13A1 in women with polycystic ovary syndrome

The polycystic ovary syndrome (PCOS), characterized by hyperandrogenism, is one of the most common hormonal disorders among premenopausal women and is associated with infertility, obesity, and insulin resistance. Accumulating evidence suggests a role of the blood coagulation factor gene F13A1 in obesity (GeneBank ID: NM_000129.3). The aim of this study was to investigate the association of intronic allelic variants of the F13A1 gene with PCOS susceptibility and metabolic parameters in lean and obese PCOS women. In a case-control study, we determined an intronic F13A1 single nucleotide polymorphism (SNP) (dbSNP ID: rs7766109) in 585 PCOS and 171 control women and tested for PCOS susceptibility and associations with anthropometric, metabolic and hormonal parameters. Genotype frequencies of the F13A1 SNP rs7766109 were equivalent in PCOS and control women. In PCOS women, F13A1 gene variants were significantly associated with body mass index (BMI) (p=0.013), systolic blood pressure (p=0.042), insulin response (AUCins) (p=0.015), triglycerides (TG) (p=0.001), and high density lipoprotein cholesterol (HDL) (p=0.012). In the subgroup of obese PCOS women free androgen index (FAI), free testosterone and sex hormone binding globulin (SHBG) as well as glucose measurements showed a significantly different pattern across F13A1 gene variants (p=0.043; p=0.039 and p=0.013, respectively). We report for the first time an association of the F13A1 SNP rs7766109 with BMI, androgens, and insulin resistance in PCOS women. Further studies are needed to confirm our findings and to evaluate whether F13A1 is causally involved in the pathogenesis of PCOS related metabolic and hormonal disturbances.     

Oral glucose tolerance test in polycystic ovary syndrome

OGTT was used to clarify the problem of hyperinsulinism and insulin resistance previously investigated by us in PCOS, using the tolbutamide test. The results of this latter investigation were in agreement with the previous found by us and with the similar already reported by other Authors. 26 women (7 obese), aged 14-34 years, affected by PCOS, were studied. The diagnosis of PCOS was made using clinical, hormonal, radiologic and echographic criteria. 16 age matched healthy women were used as controls. Glucose and insulin curves, glucose (GA) and insulin (IA) response areas and IA/GA ratio (insulin resistance in dex-IRI-) were studied by OGTT. Blood insulin values of patients resulted significantly more elevated than that of controls at any point of the curve and more significantly elevated were decreasing values. Mean values of insulin peaks, of insulin areas and of IRI resulted more elevated than that of controls. The presence of both an hyperinsulinism and an insulin resistance in PCOS seems therefore evident. A correlation was found between IRI values and plasma testosterone levels in non obese patients with increased urinary 17-ketosteroid output. A relationship between hyperandrogenism on one hand and hyperinsulinism and insulin resistance on the other is suggested.     

Ghrelin,内脂素和护骨素在Ⅱ型糖尿病发病机制中的作用研究

目的:探讨护骨素(osteoprotegerin)、内脂素(visfatin)和生长激素释放肽(ghrelin)在2型糖尿病(T2DM)代谢综合症发病机制中的作用。方法:采集受试者血清血样116例(39例2型糖尿病代谢综合症较轻组;48例2型糖尿病代谢综合症较重组;29例正常对照组)。采用酶催法检测血糖和血脂。采用ELISA法测定护骨素、内脂素、生长激素释放肽和胰岛素水平。结果:与对照组相比,糖尿病代谢综合症较轻组患者护骨素和内脂素水平显著增高,生长激素释放肽水平显著降低(P0.05)。此外,2型糖尿病兼代谢综合症较重组患者体内护骨素和内脂素水平明显高于较轻组患者(P0.05)。采用ROC曲线研究标记物最佳剂量值。2型糖尿病兼代谢综合症较重组患者护骨素(1.06 ng/m L)、内脂素(32.27 ng/m L)和生长激素释放肽(33.65 pg/m L)可分别表现出76%、92%和39.1%灵敏性及41%、69.2%和62.9%特异性。在研究的这些参数中,内脂素是预测糖尿病患者兼代谢综合症的有效指标(P0.05)。结论:护骨素、内脂素和生长激素释放肽可能作用于糖尿病患者的发病过程。内脂素是预测糖尿病患者兼代谢综合症的有效指标。     

Metabonomics reveals plasma metabolic changes and inflammatory marker in polycystic ovary syndrome patients

Polycystic ovary syndrome (PCOS) is a common, clinically heterogeneous endocrine disorder affecting women of reproductive age, associated with endocrinopathy and metabolic abnormalities. Although some metabolic parameters have been investigated, very little information has been reported on the changes of small metabolites in biofluids. The aim of this study was to establish the metabolic profile of PCOS and compare it with that of controls. In this cross-sectional study of 34 women with PCOS and 36 controls, contents of small metabolites and lipids in plasma samples were measured using nuclear magnetic resonance (NMR)-based techniques and analyzed using multivariate statistical methods. Significant decrease (P < 0.05) in the levels of amino acids (leucine, isoleucine, methionine, glutamine, and arginine), citrate, choline, and glycerophosphocholine/phosphocholine (GPC/PC), and increase (P < 0.05) in the levels of lactate, dimethylamine (DMA), creatine, and N-acetyl glycoproteins were observed in PCOS patients compared with the controls. Subgroups of patients with obesity, metabolic syndrome, or hyperandrogenism exhibited greater metabolic deviations than their corresponding subgroups without these factors. PCOS patients have perturbations in amino acid metabolism, the tricarboxylic acid (TCA) cycle, and gut microflora, as well as mild disturbances in glucose and lipid metabolism. The elevated level of N-acetyl glycoproteins demonstrates the existence of low-grade chronic inflammation in PCOS patients.     

Intravenous glucose tolerance test in the polycystic ovary syndrome

The problem of hyperinsulinism and insulin resistance, previously observed by us in PCOS using the tolbutamide test, was studied in the present research using intravenous glucose tolerance test (IVGTT). 16 women (3 obese) aged 14-34 years, affected by PCOS, were studied. The diagnosis of PCOS was made using clinical, hormonal, radiologic and echographic criteria. 8 age matched healthy women were used as controls. Glucose and insulin curves, glucose (GA) and insulin (IA) response areas and IA/GA ratio (insulin resistance index-IRI-) were studied by IVGTT. Both the mean insulin peak and the mean insulin area were significantly more elevated in patients than in controls. Average IRI value also was significantly higher than that of controls. The presence of both an hyperinsulinism and an insulin resistance is shown by the higher values in patients compared to controls. No correlation was found between either insulin areas or IRI values with plasma testosterone and urinary dehydroisoandrosterone, whereas correlations were demonstrated in previous studies, using OGTT, by us and other Authors and by us using tolbutamide test. The difference in the nature of the various stimuli performed seems to explain the different results.     

Evaluation of insulin resistance and plasma levels for visfatin and resistin in obese and non-obese patients with polycystic ovary syndrome

This study was designed to evaluate insulin resistance and plasma levels of visfatin and resistin in obese and non-obese patients with polycystic ovary syndrome (PCOS).A total of 37 premenopausal PCOS patients with (n = 18, mean (SD) age: 27.5 (5.7 years) or without obesity (n = 19, mean (SD) age: 23.7 (3.1) years) and healthy volunteers (n = 18, mean (SD) age:29.8 (4.1) years) were included in this study. Data on clinical characteristics, glycemic parameters and lipid parameters were recorded for each subject as were plasma visfatin and resistin levels. Mean (SD) HOMA-IR values were significantly higher in obese PCOS patients (3.4 (1.7)) compared with non-obese PCOS patients (2.0 (1.2), p<0.01) and controls (1.6 (0.8), p<0.01). No significant difference was noted between study groups in terms of plasma resistin (ng/mL) or visfatin (ng/mL) levels. There was no correlation between serum plasma visfatin (r = 0.127, p = 0.407) and resistin (r = -0.096, p = 0.544) levels and HOMA-IR. In conclusion, our findings revealed increased likelihood of metabolic and dyslipidemic manifestations in obese compared to non-obese PCOS patients, while no significant difference was noted in visfatin and resistin levels among PCOS patients in terms of co-morbid obesity and in comparison to controls.     

The possibility of prevention of type 2 diabetes

INTRODUCTION: The aim of this study was to examine usefulness of oral glucose tolerance test (OGTT) in clinical evaluation of different glucose metabolism disturbances in subjects with at least one risk factor of type 2 diabetes. We compared the effectiveness of non-pharmacological and pharmacological prevention and treatment regiments on metabolic control in these individuals. MATERIAL AND METHODS: The study involved 130 patients, with the following characteristics: age between 18 to 76 years, mean body mass index (BMI) - 31.82 +/- 7.24 kg/m(2), and presence of at least one of the risk factor of type 2 diabetes. Glucose metabolism disturbances were diagnosed according to World Health Organization (WHO) criteria. Non-pharmacological regiments were applied for 3 months for patients with impaired glucose tolerance (IGT) and type 2 diabetes. Patients, whose still met criteria for type 2 diabetes during OGTT after non-pharmacological treatment were scheduled for pharmacological interventions. These patients were assigned at random to two groups, that were treated with either metformin or acarbose. The measurements of total cholesterol (TC), HDL-cholesterol , LDL-cholesterol, trigliceryde (TG), glucose, HbA(1c) and/or OGGT were performed during each visit. We also assessed risk factors for type 2 diabetes in these subjects. RESULTS: The prevalence of abnormal glucose tolerance in subjects with at least one of the risk factor of diabetes type 2 was near 40%. OGTT in these subjects increased the possibility of diagnosis diabetes type 2 and IGT. Hypertension (81%), hypercholesterolemia (71.4%), hypertriglicerydemia (71.4%) and obesity (66.7%) were the most frequent risk factors observed. There were no differences in biochemical measurements between these groups of patients. CONCLUSIONS: Individuals with at least one risk factor of type 2 diabetes should have screening test to diagnose glucose intolerance. Both non-pharmacological and pharmacological intervention was effective in normalization of glucose OGTT in patients with diabetes type 2 and IGT in newly diagnosed with disease patients.     

Body fat distribution has no effect on serum visfatin levels in healthy female subjects

Obesity is the presence of either abnormal absolute amount or relative proportion of body fat. Contrary to gluteal obesity, visceral obesity is associated with different metabolic alterations including insulin resistance (IR). A relatively new adipocytokine visfatin is shown to be expressed predominantly in visceral fat and exhibit insulin-mimicking effects in rodents. It is still unclear whether serum visfatin levels are associated with increased total or visceral fat mass in humans. The aim of our study was to investigate the relation between visfatin and obesity parameters namely body mass index (BMI) and waist circumference (WaC) and IR in healthy female subjects. Eighty one female subjects ?20 years of age, having no diagnosis of glucose intolerance or diabetes, hypertension and dyslipidemia were chosen. The patients were divided into four groups according to their BMI and WaC values. Serum visfatin and HOMA-IR levels did not differ among groups. No correlation was detected between serum visfatin levels and obesity and metabolic parameters. In conclusion, we demonstrated that body fat distribution did not affect serum visfatin levels in healthy female subjects. Further studies are needed to clarify the exact factors influencing and determining serum visfatin levels and its clinical reflections.     

Is polycystic ovary syndrome associated with high sympathetic nerve activity and size at birth?

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disturbance among women of reproductive age and is proposed to be linked with size at birth and increased prevalence of cardiovascular disease. A disturbance in the sympathetic nervous system may contribute to the etiology of PCOS. This study evaluates sympathetic outflow in PCOS and its relation to size at birth. Directly recorded sympathetic nerve activity to the muscle vascular bed (MSNA) was obtained in 20 women with PCOS and in 18 matched controls. Ovarian ultrasonographic evaluation, biometric, hormonal, and biochemical parameters were measured, and birth data were collected. Women with PCOS had increased MSNA (30 +/- 8 vs. 20 +/- 7 burst frequency, P < 0.0005) compared with controls. MSNA was positively related to testosterone (r = 0.63, P < 0.005) and cholesterol (r = 0.55, P = 0.01) levels in PCOS, which, in turn, were not related to each other. Testosterone level was a stronger predictor of MSNA than cholesterol. Birth size did not differ between the study groups. This is the first study to directly address sympathetic nerve activity in women with PCOS and shows that PCOS is associated with high MSNA. Testosterone and cholesterol levels are identified as independent predictors of MSNA in PCOS, although testosterone has a stronger impact. The increased MSNA in PCOS may contribute to the increased cardiovascular risk and etiology of the condition. In this study, PCOS was not related to size at birth.     

Utilidad de la hemoglobina A1c en el diagnóstico de diabetes mellitus y otras alteraciones del metabolismo glucídico en mujeres con diabetes mellitus gestacional reciente

IntroductionWomen with gestational diabetes mellitus (GDM) have an increased risk for developing diabetes mellitus (DM). Their postpartum metabolic classification using a 75 g oral glucose tolerance test (75 g OGTT) is recommended. The purpose of this study was to assess the value of hemoglobin A1c for postpartum evaluation in women with recent gestational diabetes mellitus.Patients and methodsFifty-six women with recent GDM underwent a 75 g OGTT at our center to assess postpartum changes in carbohydrate metabolism and were classified using diagnostic criteria of the American Diabetes Association (ADA). Receiver operating characteristic (ROC) curves analysis was used to assess the diagnostic performance of hemoglobin A1c, and kappa index was used to evaluate diagnostic agreement between hemoglobin A1c and 75 g OGTT.ResultsDM was diagnosed in 7 women, and other categories of increased risk for DM in 25 women. Kappa index for diagnosis agreement was 0,22. Hemoglobin A1c ≥ 5.7% had 47% sensitivity and 71% specificity for identifying any change in carbohydrate metabolism. A hemoglobin A1c value ≥ 6.5 had 29% sensitivity and 100% specificity for diagnosis of DM. Area under the ROC curve was 0.57 for identifying any change in carbohydrate metabolism and 0.81 for diagnosis of DM.ConclusionUsing ADA cutoff values, hemoglobin A1c is not appropriate for postpartum glucose tolerance evaluation in women with recent gestational diabetes mellitus.     

Assessing Impaired Glucose Tolerance and Insulin Resistance in Polycystic Ovarian Syndrome with A Muffin Test: An Alternative to the Glucose Tolerance Test

ObjectiveTo determine the sensitivity of a high-glucose load in a meal as an alternative to the standard oral glucose tolerance test (OGTT) in detecting impaired glucose tolerance and insulin resistance in women with polycystic ovarian syndrome (PCOS) and the relationship of body composition to insulin resistance in the PCOS cohort.MethodsIn this prospective, single-center study, women with PCOS who were being followed up as outpatients were recruited. The study was performed between November 2007 and March 2008. All participants underwent OGTT before study enrollment. Participants were given a meal including carbohydrates, fat, and protein. Glucose and insulin levels were measured every 30 minutes for 2 hours after completing the meal. Body composition was measured by dual-energy x-ray absorptiometry.ResultsThirteen of the 15 participants completed the meal tolerance test and the body composition study. Four of 13 participants (31%) had abnormal glucose tolerance with the meal test compared with 2 of 8 participants (25%) who completed the OGTT. Those who had insulin resistance on OGTT were detected with the meal test. The 2-hour insulin levels following the meal were 38% higher than with the OGTT. Of 10 participants with insulin resistance, 9 had a total body fat mass greater than the 90th percentile, whereas 1 of 3 participants (33%) with normal body composition was insulin resistant.ConclusionAdministration of oral glucose load via a meal is an effective alternative to the OGTT in diagnosing impaired glucose tolerance and insulin resistance and may be more sensitive, without the adverse effects of the oral glucose load in the OGTT. PCOS is an independent risk factor for impaired glucose tolerance and insulin resistance, regardless of body composition. (Endocr Pract. 2010;16:810-817)     

Clinical and biochemical characterization of women with polycystic ovary syndrome in North Rhine-Westphalia.

Polycystic ovary syndrome (PCOS), defined as the combination of oligoanovulation and hyperandrogenism, affects more than 5% of women of reproductive age. Insulin resistance and hyperinsulinemia appear to play an important role in its pathogenesis. Here, we will present a characterization of a PCOS cohort from North Rhine-Westphalia in Germany. Clinical features, family history as well as endocrine and metabolic parameters were prospectively recorded from 200 successive patients. All patients were evaluated for insulin resistance and beta-cell-function by oral glucose tolerance test. Patient data were compared with those of 98 age-matched control women. PCOS patients showed significantly higher BMI, body fat mass and androgen levels as well as impaired glucose and insulin metabolism. A positive family history of PCOS and diabetes was more frequent in PCOS patients. Insulin resistance (71%) was the most common metabolic abnormality in PCOS patients followed by obesity (52%) and dyslipidemia (46.3%), with an incidence of 31.5% for the metabolic syndrome. C-reactive protein and other cardiovascular risk factors were frequently elevated even in young PCOS patients. While the clinical characteristics and endocrine parameters of this German PCOS cohort were heterogeneous, they were comparable to those from other Caucasian populations.     

Role of D327N sex hormone-binding globulin gene polymorphism in the pathogenesis of polycystic ovary syndrome

SHBG (sex hormone-binding globulin) is a transport protein specific for dihydrotestosterone, testosterone and estradiol. The missense mutation in exon 8 (GAC-->AAC) causing the amino acid exchange Asp-->Asn in codon 327 (D327N) correlates according to the published data with increased SHBG levels. We studied possible association of this polymorphism with polycystic ovary syndrome (PCOS) and anthropometric and biochemical parameters in 248 PCOS patients and 109 healthy control women. The D327N polymorphism (wild-type and variant allele) was detected using PCR-RFLP method (restriction enzyme Bbs-I). For statistical evaluation chi(2) test, Mann-Whitney test, ANCOVA, ANOVA (NCSS 2004, Statgraphics Plus v.5.1, USA) were used. There was no significant difference in genotype distribution between PCOS and controls (chi(2)=1.03, p=0.59). Moreover, we did not find an association of the variant allele with plasma SHBG level, steroid hormones, or screened parameters of lipid and glucose metabolism. In conclusion, the D327N polymorphism of the SHBG gene does not influence susceptibility to PCOS.     

Susceptibility loci for polycystic ovary syndrome on chromosome 2p16.3, 2p21, and 9q33.3 in a cohort of Caucasian women

In a recent genome-wide association study investigating Han Chinese PCOS women 3 loci that are strongly associated with PCOS were identified on chromosome 2p16.3 (rs13405728), 2p21 (rs13429458), and 9q33.3 (rs2479106). The aim of the study was to investigate the impact of rs13405728, rs13429458, and rs2479106 variants on PCOS susceptibility in a Caucasian cohort of PCOS and control women. Metabolic, endocrine, and anthropometric measurements and oral glucose tolerance tests were performed in 545 PCOS and 317 control women. The rs13405728, rs13429458, and rs2479106 polymorphisms were genotyped. There was no significant difference in genotype frequencies of rs13405728 and rs13429458 variants between PCOS and controls. There was a trend towards an association of the rs2479106 variant with PCOS susceptibility (p=0.053). PCOS women with the rs2479106 GG genotype had significantly higher WHR than PCOS women carrying the AG and AA genotype (p=0.034 and p=0.020, respectively). Moreover, QChol/HDL and LDL levels were significantly higher in PCOS women carrying the rs2479106 GG genotype when compared to those carrying the AA genotype (p=0.024 and p=0.035, respectively). PCOS women carrying the G allele of rs13405728 had significantly higher AUCgluc, glucose-30 min, and AUCins levels than those carrying the AA genotype (p=0.039, p=0.047, and p=0.044, respectively). In PCOS women, rs13405728 genotypes are associated with glucose and insulin metabolism. Moreover, rs2479106 genotypes were associated with increased WHR levels and an adverse serum lipid profile. Further, we observed a trend towards decreased PCOS susceptibility within carriers of the rs2479106 G-allele. Further studies in large Caucasian PCOS cohorts are warranted to confirm our findings.     

Role of Androgen in Liver Fat Content in Women: Metabolically Advantageous or Disadvantageous?

Objective: Androgens have a controversial effect on liver fat content (LFC) in androgen-excess females and androgen-deficient males. Polycystic ovarian syndrome (PCOS) is often associated with hyperandrogenism and nonalcoholic fatty liver disease. The aim of this study was to explore the association between hyperandrogenemia and increased liver fat content in women with PCOS, independent of other metabolic parameters.Methods: This case series study included 501 women with PCOS and 112 aged-matched controls in the outpatient department of a tertiary hospital. Anthropometric measurements, hepatic and renal function, glucose and lipid metabolism parameters, and sex hormones were examined in these women. LFC was measured by quantitative ultrasonography.Results: Women with hyperandrogenism (P<.001), an oligomenorrhoea/anovulation phenotype (P = .0064), and a diagnosis of PCOS (P<.001) had higher LFC. Androgen level is an important factor among the 9 independent risk factors of LFC (P = .0239) and may have a dimorphic impact on LFC. In all women, when the free androgen index (FAI) was less than 41.94, LFC increased with the elevated FAI; when the FAI was greater than 41.94, LFC decreased with the elevated FAI (P<.001). In women with PCOS, receiver operating characteristic curve analysis demonstrated that LFC could at least partially predict impaired glucose regulation, impaired lipid metabolism, and insulin resistance (P<.0001 for all).Conclusion: Androgen level is associated with LFC in dimorphic directions. LFC may be a predictive factor of insulin resistance, impaired glucose regulation, and impaired lipid metabolism in women with PCOS.     

Genetic variation in the vitamin D receptor gene and vitamin D serum levels in Egyptian women with polycystic ovary syndrome

Obesity, insulin resistance, and hyperandrogenism are considered crucial parameters of polycystic ovary syndrome (PCOS) which might be related to vitamin D metabolism. The aim of this study was to investigate the associations between polymorphisms (TaqI and ApaI) in the vitamin D receptor gene (VDR) and PCOS among Egyptian women. We aimed also to elucidate the impact of these polymorphisms on vitamin D level, hormonal and metabolic parameters of PCOS. One hundred and fifty Egyptian women with PCOS and 150 unrelated controls were enrolled in this study. Polymorphisms of VDR Taq-I T/C (rs731236) and Apa-I A/C (rs7975232) gene were genotyped using polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP). Serum 25 hydroxy vitamin D [25(OH) D] levels were measured by high-performance liquid chromatography. PCOS women had significantly lower levels of 25(OH) D compared to healthy women. Our results revealed that Taq-I CC genotype and C allele were associated with increased risk of PCOS, while the Apa-I polymorphism was not. Haplotype Taq-I C/ Apa-I C was associated with a higher PCOS risk more than controls. Moreover, there was a significant decrease of 25(OH) D levels in carriers of haplotype Taq-I C/ Apa-I C (with variant alleles) compared to the non-carriers. Results showed also that there was an obesity- VDR Taq-I genotypes interactions. These results suggested that, VDR Taq-I gene polymorphism is associated with increased risk of PCOS in Egyptian women.     

Analysis of glucose tolerance in twin gestations using an oral glucose load.

The effect of twin gestation on carbohydrate metabolism was evaluated using a 75 g oral glucose tolerance test (75 g OGTT). A 75 g OGTT was performed in 63 twin gestations and 3 791 singleton gestations during the third trimester. Plasma glucose concentrations were measured in the pregnant women under fasting conditions as well as 30 min, 1 h, and 2 h after ingestion of glucose (75 g oral load), and serum insulin concentrations were measured in fasting and 30 min post-ingestion samples. Women with twin gestations showed significantly lower plasma glucose concentrations during fasting and 30 min after the glucose load in the samples taken than those with singleton gestations. No significant difference in serum glucose concentrations was found in the other specimens. There were no cases of gestational diabetes mellitus in our study. Although women with twin gestations demonstrated lower plasma glucose concentrations than women with singleton gestations, the difference observed was subtle. We could not find any significant differences in these plasma glucose values as used to define a pathologic OGTT between twin and singleton pregnancies, with the exception of the fasting value.