Sex Hormone-binding Globulin Gene Research Articles

SHBG and Insulin resistance - Nexus revisited.

Sex hormone binding globulin (SHBG) is a liver-synthesized glycoprotein. Low SHBG levels are associated with insulin resistance (IR). Specific single nucleotide polymorphisms (SNPs) in the SHBG gene are linked to IR. Therefore, it is of interest to provide a review on the comprehensive overview for SHBG related to IR.

Recent Advances on Sex Hormone-Binding Globulin Regulation by Nutritional Factors: Clinical Implications.

Sex hormone-binding globulin (SHBG) is a homodimeric glycoprotein produced by the human liver and secreted into the systemic circulation where it binds with high affinity sex steroids regulating their availability in blood and accessibility to target tissues. Plasma SHBG levels are altered in metabolic disorders such as obesity, anorexia, and insulin resistance. Several reports have shown that diets in terms of total calories or fat, fiber, or protein content can alter plasma SHBG levels. However, there are many components in a diet that can affect SHBG gene expression in the liver. In order to unravel the molecular mechanisms by which diets regulate SHBG production, it would be necessary to analyze single diet components and/or nutritional factors. This review summarizes the recent advances in identifying different nutritional factors regulating SHBG production and the related molecular mechanism, as well as the clinical implications.

Investigating the Interplay of Lipid Profile and Sex Hormone binding globulin Gene Polymorphism in Postmenopausal Women with Type 2 Diabetes

Investigating the Interplay of Lipid Profile and Sex Hormone binding globulin Gene Polymorphism in Postmenopausal Women with Type 2 Diabetes

SHBG gene polymorphisms and their influence on serum SHBG, total and free testosterone concentrations in men.

Genetic variation in sex hormone-binding globulin (SHBG) structure may affect estimates of sex steroid exposure by altering the affinity of the protein for its ligand. Consequently, free hormone calculations assuming constant binding affinity may, for certain genetic variations, lead to incorrect diagnoses if genetic variation is not taken into consideration. To investigate the effects of genetic variation in SHBG on calculated and measured serum free testosterone (T) in men. Population-based sibling-pair study in 999 healthy men aged 25 to 45 (mean: 34.5) years. Genotyping using microarray (Illumina®) for SNPs suggested to affect binding affinity and/or concentration of SHBG or T. SHBG concentrations were measured using immunoassay and in a subset (n = 32) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Total T was measured using LC-MS/MS. Free T was calculated and in a subset (n = 314) measured directly using LC-MS/MS after equilibrium dialysis. Allelic frequencies of analyzed SNPs ranged from 0.5% to 58.2%. Compared to wild-type, SHBG concentrations were lower in rs6258 heterozygotes (-24.7%; p < 0.05) and higher in rs6259 heterozygotes, rs727428 homozygotes, and carriers of rs1799941 (+10.8 to 23.1%; all p < 0.05). Total T was higher in rs727428 homozygotes and carriers of rs5934505, rs1799941and rs6259 (+3.9 to 21.4%; all p < 0.05). No clear effects on measured free T were found, except for a trend towards higher values in rs6259 homozygotes, significant for calculated free T (+18.7%; p < 0.05) in the larger global study population. In these men, analyzed SNPs were relatively prevalent and affected serum concentrations of total T and SHBG but not calculated or measured free T except for a higher trend in rs6259 homozygotes.

Genetic regulation of testosterone level in overweight males from the Kazakh population and its association with hypogonadism.

Male hypogonadism and erectile dysfunction in different populations are associated with excess body weight. A key aspect in most studies is the metabolism of sexual hormones, primarily testosterone. At the same time, the binding protein sex hormone binding globulin (SHBG) can play a large role, as it determines the ratio of total and bioavailable testosterone in blood, i.e. both the hormone content and level of its production. Recent research has identified common mutations that affect SHBG levels, such as the rs727428 polymorphic locus, which is associated with alterations in histone protein function, affecting the regulation of ribonucleic acid (RNA) protein SHBG synthesis. Similar relationships have been observed for prevalent mutations, including rs5934505 and rs10822184, in diverse populations. This study involved 300 individuals of Kazakh nationality from the Eastern Kazakhstan region, examining three polymorphic variants of the SHBG gene (rs727428, rs5934505, and rs10822184). The participants were categorized into three groups: individuals with hypogonadism and obesity (group 1, n=85), those with excess body weight but no hypogonadism (group 2, n=70), and individuals with neither excess body weight nor hypogonadism (group 3, n=145). The frequency of mutant gene alleles impacting GPS (SHBG) synthesis in the Kazakh population was notably high, comparable to European and South-East Asian populations. However, the association between excess body weight and these mutations exhibited varying patterns. Hypogonadism was linked to decreased GPS levels, strongly correlating with total testosterone but not bioavailable testosterone. The retention of sexual functions in overweight men was not always directly related to BMI levels and GPS concentrations.

Association of sex hormone-binding globulin gene polymorphism and sex hormone-binding globulin levels in postmenopausal women in relation to type 2 diabetes mellitus – A case–Control study

Association of sex hormone-binding globulin gene polymorphism and sex hormone-binding globulin levels in postmenopausal women in relation to type 2 diabetes mellitus – A case–Control study

Transforming growth factor-beta 1: A new factor reducing hepatic SHBG production in liver fibrosis.

Low plasma sex hormone-binding globulin (SHBG) levels are present in fatty liver disease, which represents a spectrum of diseases ranging from hepatocellular steatosis through steatohepatitis to fibrosis and irreversible cirrhosis. We have previously determined that fat accumulation reduces SHBG production in different nonalcoholic fatty liver disease mouse models. In the present work, we are interested in elucidating the molecular mechanisms reducing SHBG plasma levels in liver fibrosis. For this purpose, in vivo studies were performed using the human SHBG transgenic mice developing liver fibrosis induced by carbon tetrachloride (CCl4 ). Our results clearly showed that CCl4 induced liver fibrosis and reduced SHBG production by reducing hepatocyte nuclear factor 4 alpha (HNF-4α). The SHBG reduction could be influenced by the increase in transforming growth factor-beta 1 (TGF-β1), which was increased in mice developing liver fibrosis. Therefore, we decided to evaluate the role of TGF-β1 in regulating hepatic SHBG production. Results obtained in both HepG2 cells and human SHBG transgenic mice showed that TGF-β1 reduced significantly SHBGmessenger RNA and protein levels. Mechanistically TGF-β1 downregulated P1-HNF-4α isoforms and increased P2-HNF-4α isoforms via Smad3 and Stat3 pathways through TGF-β1 receptor I, resulting in transcriptional repression of the SHBG gene. Takentogether, we found for the first time that TGF-β1 is a new factor regulating hepatic SHBG production in liver fibrosis. Further research is needed to determine the role of this reduction in hepatic SHBG production in the progression of nonalcoholic steatohepatitis.

Decreased risk of ovarian cancer associated with rs9898876 sex hormone-binding globulin gene variant.

Ovarian cancer (OC) is one of the most common gynecologic cancers,with significant morbidity and mortality. The risk of OC is influenced by hormone status, of which sex hormone-binding globulin (SHBG), which influences the serum availability of steroid sex hormones, is implicated in the pathogenesis and evolution of OC. The aim of this study is to evaluate the involvement of common SHBG gene variants in OC susceptibility and evolution. A case control study including 71 OC patients and 74 cancer-free controls, who were genotyped for rs9898876, rs13894, rs1799941 and rs6257 SHBG SNP. Genotyping was done by the allelic discrimination method, using VIC- and FAM-labeled primers. The minor allele frequencies of rs9898876, rs13894, rs1799941 and rs6257 SHBG SNP was comparable between OC cases and control women, implying no significant associations of the tested variants and overall OC risk. Taking homozygous wild-type genotype as reference (OR = 1.00), heterozygous rs9898876 (G/T), and minor allele-carrying genotypes [G/T + T/T] were associated with reduced risk of OC. While rs9898876 heterozygosity (G/T) was predictive of OC occurrence, no significant association of the remaining three tested SNPs was noted with altered risk of OC. Irrespective of FIGO staging, the four tested SHBG SNPs were not associated with the clinical progression of OC. In conclusion, SHBG rs9898876 is associated with a decreased risk of OC, and thus constitutes a potential diagnostic biomarker of OC.

Effect of Sex Hormone-Binding Globulin on Polycystic Ovary Syndrome: Mechanisms, Manifestations, Genetics, and Treatment.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases causing infertility in women of childbearing age. It is characterized by hyperandrogenemia (HA), chronic anovulation, and polycystic ovary morphology (PCOM). Most women with PCOS have metabolic abnormalities. Sex hormone-binding globulin (SHBG), a transport carrier that binds estrogen and androgens and regulates their biological activity, is usually used as an indicator of hyperandrogenism in women with PCOS. Low serum SHBG levels are considered a biomarker of metabolic abnormalities and are associated with insulin resistance (IR), HA, and abnormal glucose and lipid metabolism in PCOS patients. SHBG is also related to the long-term prognosis of PCOS, whereas SHBG gene polymorphism is associated with PCOS risk. In addition, the administration of metformin (MET), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), thiazolidinediones (TZDs), compound oral contraceptives (COCs), as well as nutrient supplements such as inositol (MI), vitamin D, and synbiotics can regulate SHBG levels to ameliorate PCOS complications and improve prognosis. This review focuses on the interaction between SHBG and various PCOS complications as well as the regulation of SHBG by various drugs and nutrients and its therapeutic effects on PCOS.

The effect of sex hormone-binding globulin gene polymorphisms on the serum level of SHBG hormone in the men with prostate cancer

To evaluated the possible correlations of prostate cancer and three coding region polymorphisms (rs 6257, rs6258, rs 6259), & changing repeat of TAAAA in promoter of SHBG gene regarding to concentration of Prostate specific Antigen and SHBG levels. For study purpose, a total of 352 subjects (176 patients and 176 controls) were recruited. The ELISA technique and the RFLP-PCR method were used. Logistic and adjusted regression of genotypes showed that the (TAAAA)n polymorphism in individuals carrying more than five repeats of the five-nucleotide sequence of TAAAA, as well as AA+AG (rs6257) and AA+AG (rs6259), increased the risk of prostate cancer by the chance ratio of 1.622, 2.005, and 2.469, respectively. The studied polymorphisms showed a significant relationship with the stage of the disease and Gleason score. The individuals carrying the mutants were less likely to develop prostate cancer than the ones with wild genotypes. All the genotypes in the cancer group had higher serum levels of tPSA and fPSA than those in the control group. A significant association was observed (except tPSA and fPSA for GT (rs6258) and fPSA for GA (rs6259)). Serum level of SHBG also showed a significant correlation with prostate cancer in genotypes >Panta TAAAA (TAAAA)n, GG (rs6257), TT and TT + CT (rs6258), and GG, AA, and AA+GA (rs6259). These polymorphisms by changing the serum levels SHBG contributed to the incidence of prostate cancer.

Evaluation of reproductive hormones in Egyptian workers occupationally exposed to di-2-ethylhexyl phthalate (DEHP): a cross-sectional study.

Di-2-ethylhexyl phthalate (DEHP) is ubiquitous, known as an endocrine disruptor. DEHP is a widespread prevalence in general and occupational populations which raised great public concerns due to its potentially harmful health effects on the male reproductive system. We aimed to assess occupational levels of DEHP on gonadotropin and gonadal hormones including luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone (TT), and sex hormone binding globulin (SHBG) and evaluate its potential effects on Asp327Asn polymorphisms SHBG gene. We measured the levels of DEHP of 90 male workers in one of polyvinyl chloride (PVC) industry plant using enzyme-linked immunosorbent assay. Sex hormones were examined and Asp327Asn polymorphisms SHBG gene were detected by PCR-RFLP in all participants. The workers were divided into low- and high- DEHP exposed groups based on the geometric mean (GM) levels (183.86U/L) in serum. TT and TT: LH ratio were negatively correlated to DEHP levels (r=-0.213, p=0.038), (r=-0.225, p=0.027), respectively. The linear regression analysis revealed that a 10-fold increase of serum DEHP was found to be associated with 2.07 fold decreased in TT and a 2.26 fold decreased in TT/LH ratio. Serum testosterone is negatively associated with DEHP exposure in occupational workers.

Association between sex hormones regulation-related SNP rs12233719 and lung cancer risk among never-smoking Chinese women.

BackgroundThe mechanism of rapidly increased non‐small cell lung cancer (NSCLC) among never‐smoking Chinese women has not been elucidated. Ovarian sex steroid hormones have been suggested to counteract lung cancer development, and sex hormone‐binding globulin (SHBG) is essential in sex hormones regulation. This study aims to exploring single nucleotide polymorphisms (SNPs) in genomic regions associated with SHBG concentrations that contributed to never‐smoking female NSCLC.MethodsCandidate genes were selected by a genome‐wide association (GWAS) meta‐analysis and gene expression profiles of never‐smoking NSCLC of Chinese women. The candidate SNPs limited to common minor allele frequency (MAF), missense variant, ethnic heterogeneous distribution, and SNPs were genotyped using the TaqMan method. A two‐stage case‐control design was adopted for exploration and validation of associations between candidate SNPs and risk of NSCLC. All participants were never‐smoking Chinese women. Chi‐square test and multivariate logistic regression were applied.ResultsBeginning with 12 genomic regions associated with circulating SHBG concentrations and gene expression profiles from never‐smoking NSCLC in Chinese women, candidate SNP rs12233719 and rs7439366 both located in candidate gene UGT2B7, which may be related to circulating SHBG concentrations and cancer risk, were identified. A two‐stage case‐control study was conducted in Shenyang and Tianjin represented as the training stage and validation stage, respectively. Under the dominant model, compared to individuals with the wild G/G genotype, the adjusted OR of those with the T allele was 1.58 (95% CI: 1.15–2.16) in Chinese Shenyang training set, and was 1.49 (95% CI: 1.02–2.18) in Chinese Tianjin validation set, both accompanied with a significant trend relationship consistently. UGT2B7 was upregulated in female NSCLC patients’ tumor tissues and was associated with a poor prognosis in NSCLC.ConclusionOur findings indicated that a sex hormones regulation‐related SNP rs12233719 was associated with never‐smoking female lung cancer risk, which might partially explain NSCLC‐susceptibility in Chinese women.

Relationship of Breast Cancer Susceptibility with Rs6257 and Rs6258 Polymorphisms in the SHBG Gene

Background: Breast cancer is a hormone-dependent malignancy. Sex hormone-binding globulin (SHBG) is the main transport binding protein for sex steroid hormones in plasma and regulates their accessibility to target cells. Objective: The present study aimed to assess the relationship between rs6257 and rs6258 polymorphisms in the SHBG gene with breast cancer risk. Materials and Methods: This case-control study was conducted on 100 breast cancer patients and 100 healthy control subjects. After extracting DNA from peripheral blood, Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. The data were analyzed in SPSS software using the chi-square test and logistic regression to distinguish the difference between the cases and controls in terms of the distribution of allele types and genotypes. Results: The frequencies of Rs6257 were 78%, 17%, 5% in the case group and 88%, 7%, and 5% in control groups for TT, CC, and CT genotypes respectively. The rs6257 CC genotype showed about a 2.721-fold increase in breast cancer (P=0.030, OR:2.721, CI95%:1.075-6.887). This genotype was reversely associated with age, body mass index, menopausal status, and breast cancer. Nonetheless, Rs6258 had no significant correlation with breast cancer risk or other demographic factors. Conclusions: As evidenced by the obtained results, the rs6257 polymorphism may be a useful biomarker associated with breast cancer risk in Iranian women. To confirm the findings of the present study, larger studies are needed in the future.

Association of the Genetic Polymorphisms rs6259 and rs727428 of the SHBG Gene with Polycystic Ovary Syndrome Risk: A Meta-Analysis.

Background: Studies investigating the relationship between polymorphisms of the sex hormone-binding globulin (SHBG) gene and polycystic ovary syndrome (PCOS) have reported differing results. Therefore, the present meta-analysis was performed to clarify the effects of the SHBG rs6259 and rs727428 polymorphisms on PCOS risk. Materials and Methods: Published English language studies were selected through an extensive search of the Web of Science, PubMed, and EMBASE databases. Chinese studies were identified using Wan Fang, VIP, and the Chinese National Knowledge Infrastructure (CNKI) databases. The pooled odds ratio and 95% confidence interval were calculated using the random-effects model. Subgroup analyses and heterogeneity analyses were also performed. Results: A total of 1660 cases and 1312 controls were included in this meta-analysis. We found that the SHBG rs6259 polymorphism was not significantly associated with an increased risk of PCOS in any of the genetic models with significant heterogeneity; the results were consistent for all subgroups. A nonsignificant association between the rs727428 polymorphism and an increased risk of PCOS was also detected in all genetic models. Conclusions: The findings of this meta-analysis suggest that neither the SHBG rs6259 nor rs727428 polymorphism are associated with susceptibility to PCOS. However, because of the considerable heterogeneity and the small sample size, these pooled results should be interpreted with caution.

Effects of SHBG rs1799941 Polymorphism on Free Testosterone Levels and Hypogonadism Risk in Young Non-Diabetic Obese Males.

Introduction: Obesity has been associated with increased risk of presenting hypogonadism. Free testosterone (FT) is the fraction of testosterone that carries out the biological function of testosterone, and is determined from total testosterone (TT) and sex-hormone binding globulin (SHBG) levels. We aimed to study the SHBG polymorphism rs1799941 in a cohort of young non-diabetic obese males to unravel the possible implication of this polymorphism in obesity-related hypogonadism. Methodology: 212 young (<45 years) non-diabetic obese (BMI ≥ 30 kg/m2) males participated in this study. Subjects were classified according to TT and FT levels in: Eugonadal (n = 55, TT > 3.5 ng/mL and FT ≥ 70 pg/mL; EuG), normal FT hypogonadism (n = 40, TT < 3.5 and FT ≥ 70 pg/mL; normal FT HG) and hypogonadism (n = 117, TT < 3.5 ng/mL and TL < 70 pg/mL; HG). The SHBG rs1799941 polymorphism (GG/GA/AA) was analyzed using the Taqman Open Array (Applied biosystem). Results: The rs1799941 frequencies were different among the groups. Higher proportion of the allele (A) was found in HG, compared to EuG and normal FT HG. Among the genotypes, the rare homozygous (AA) were found in the normal FT HG group and higher levels of serum SHBG and lower of FT were observed. The presence of the allele A was related (according to lineal regression models) to an increased of SHBG levels ((GA) β = 3.28; (AA) β = 12.45) and a decreased of FT levels ((GA) β = −9.19; (AA) β = −18.52). The presence of the allele (A) increased the risk of presenting HG compared to normal FT HG (OR = 2.54). Conclusions: The rs1799941 of the SHBG gene can partially determine the presence of obesity-related hypogonadism in young non-diabetic males and whether these subjects have normal FT HG.

Genetic polymorphisms of the SHBG gene can be the effect on SHBG and HDL-cholesterol levels in Coronary Heart Disease: a case-control study.

Sex hormone binding globulin (SHBG) level is positively associated with the high-density lipoprotein cholesterol (HDL-C) levels. The aim of this study was to investigate the effects of the SHBG gene variations (D356N, rs1799941, and P156L) on SHBG and HDL-C levels and Coronary Heart Disease (CHD) risk. The SHBG D356N (rs6259,G > A), P156L (rs6258,C > T), and rs1799941(G > A) polymorphisms were determined in 131 male CHD patients and 55 male controls by PCR-RFLP and real-time PCR techniques. SHGB levels were measured by Electro-chemiluminescence immunoassay (ECLIA). In the patients who had SHBG levels lower than threshold 35nmol/l value, the risk of being HDL-C levels lower than threshold 0.90mmol/l value was observed statistically significant (p = 0.017; OR 2.522, 95% CI 1.170-5.438). The rs1799941 GG was associated with increased CHD risk when compared with the A allele carriers (GA + AA) (p = 0.019, OR 2.222, 95% CI 1.130-4.371). In addition, the rs1799941 GG genotype and D356NN allele were associated with lower SHBG in the CHD group (p < 0.01). The logistic regression analysis also revealed the rs1799941 GG genotype was significantly associated with low SHBG in CHD patients. It was observed that Haplotype-1(rs1799941 G allele-P156L P allele-D356N D allele) was associated with increased CHD risk, while Haplotype-2 (rs1799941 rare A allele-P156L C allele- D356N G allele) was correlated with the decreased CHD risk (p = 0.0167). Our findings suggest that there is a positive correlation between SHBG and HDL-C levels in CHD patients, and this association might be affected by SHBG gene variations.

Genetic Polymorphism in Sex Hormone-binding Globulin With a Prognosis of Androgen Deprivation Therapy in Metastatic Prostate Cancer Among Japanese Men.

Testosterone suppression in serum during androgen deprivation therapy (ADT) can affect the oncologic outcome of ADT. Although genetic variants in sex hormone-binding globulin (SHBG) were reported to be correlated with serum testosterone level, the association with serum testosterone during ADT remains unclear. Therefore, this study investigated the impact of a missense polymorphism in the SHBG gene among men treated with primary ADT for metastatic prostate cancer. This study included 104 Japanese men with metastatic prostate cancer. The association of SHBG gene polymorphism (rs6259, D356N) with clinicopathologic parameters including serum testosterone levels during ADT, as well as prognosis, including progression-free survival and overall survival, was examined. The serum testosterone levels during ADT were comparable between men carrying the homozygous wild-type (GG) and heterozygous/homozygous variant (GA/AA) in the SHBG gene. When adjusted for age, Gleason score, initial prostate-specific antigen, and clinical T-stage, the heterozygous/homozygous variant (GA/AA) in the SHBG gene was associated with a higher risk of progression (hazard ratio, 2.20; 95% confidence interval, 1.10-4.18; P= .027) and any-cause death (hazard ratio, 3.21; 95% confidence interval, 1.31-7.35; P= .012). This study suggested genetic variation in SHBG (rs6259) might be an independent prognostic biomarker among men treated with primary ADT for metastatic prostate cancer.

Common genetic variants in the sex hormone-binding globulin (SHBG) gene in idiopathic recurrent pregnancy loss: a case control study

BackgroundA role for sex hormone-binding globulin (SHBG) in determining the pregnancy outcome was evidenced by the rise in SHBG levels during pregnancy linked with favorable pregnancy, while reduction in SHBG levels and hyperandrogenemia were linked with poor pregnancy outcome. Since SHBG production is genetically determined, this study investigated the association of SHBG polymorphisms with the susceptibility to recurrent pregnancy loss (RPL).MethodsRetrospective case-control study, involving 308 women with RPL, and 310 control women RPL, defined as ≥3 consecutive miscarriages, and with the same partner, was the main outcome measure. SHBG genotyping was done by allelic exclusion method (real-time PCR).ResultsOf the seven tested SHBG SNP, lower MAF of rs6257 was seen in RPL cases than in control women, which was linked with lower risk of RPL, after controlling for key covariates. At the genotype level, significantly higher frequencies of heterozygous rs858521 and rs6259, and homozygous rs858521 genotype carriers, and reduced frequency of heterozygous rs6257 and homozygous rs6257 and rs6259 genotype carriers were seen in RPL cases vs. control women, respectively. Univariate regression analysis confirmed the positive association of rs858521 and rs6259 with RPL. Multivariate regression analysis confirmed the positive association of rs858521 heterozygote and homozygote genotypes with RPL; only heterozygous rs6259 remained associated with RPL. Haploview analysis demonstrated marked linkage disequilibrium among 6 of the 7 tested SHBG SNP. Of the possible 6-locus haplotypes, 12 were common, and were included in subsequent analysis. Within these haplotypes, only increased frequency of CCGTGA haplotypes was seen in RPL cases, thus conferring RPL susceptibility.ConclusionsSpecific SHBG variants, and SHBG haplotypes are associated with altered risk of RPL, suggesting role for SHBG as RPL candidate gene.

Testosterone levels and the genetic variation of sex hormone-binding globulin gene of Bubalus bubalis, bulls in Egypt

Testosterone is themain plasma androgen produced and secreted by male testis. To be bioactive, it binds to sex hormonebinding globulin (SHBG), i.e. the major transporter protein of sex steroids in the blood of mammals and other vertebrate species.Firstly, this study aimed to determine the levels of testosterone in different-age groups of buffalo bulls (Bubalus bubalis) in Egypt, and secondly to screen the genetic polymorphisms in their SHBG gene and to investigatewhether these polymorphisms are associated with the level of the circulating serum testosterone. Blood samples were collected from 67 Egyptian buffalo bulls representing four different age-groups and testosterone concentration was measured by radioimmunoassay. Selected DNA samples from different age-groups were sequenced for the full length of theirSHBGgene.Asignificant increase in the concentration of serum testosterone in buffalo bulls was recorded with the advancement of age from 12/18 to 24/36 months. Based on the number of polymorphisms in SHBG gene, the current study reveals the presence of three bull genotypes, of which one is likely to be associated with low testosterone concentration, while other is likely to be associated with an increased testosterone concentration. Such genetic associations can provide a good tool for the selection of bull genotypes with higher testosterone concentrations, which are indispensible for breeding purposes.

Effect of placental sex hormone-binding globulin single nucleotide polymorphism rs6259 on protein and function in gestational diabetes mellitus.

Sex hormone-binding globulin (SHBG) has a key role in the occurrence and development of the gestational diab-etes mellitus(GDM). Single nucleotide polymorphism(SNP) rs6259 is a functional site in SHBGgene, which is suspected to regulate the SHBG level. The present study explored the placental SHBGSNPrs6259 distribution in Chinese pregnant women and the influence on placental SHBG concentrations, to assess the relationship of SHBGrs6259 in the occurrence and development of GDM. We screened the SHBG rs6259 allele in 210healthy and 180GDM gravidas by PCR-RFLP and restriction enzyme and measured placental SHBG concentrations in each genotypic group with western blot analysis. The mechanisms of SHBGrs6259 function were analyzed by cell culture, recombinant lentivirus transfection, real-time PCR, and western blot analysis. We found the differences of SHBGAsn327 allele frequency and the genotype distribution in GDM and control groups were statistically significant (P<0.05). Western blot analysis results showed that the Asn327 allele group was associated with a higher placental SHBG level than the Asp327 allele homozygote group (P<0.05). In HTR8-SVneo cell transfection, the positive transfection groups (SHBG-rs6259Asn) led to an obviously higher tendency of SHBG mRNA and protein expression than the negative control groups (SHBG-rs6259Asp), the normal cell group, and the blank control group (blank lentivirus LV-5)(P<0.05). Our data, therefore, reflected that SHBGSNPrs6259 causes changes in placental SHBG concentration and may play a functional role in the molecular mechanisms of GDM etiology.