Insight into the correlation between microbial diversity and flavor profiles of traditional dry-cured duck from the metabolomic perspective.

The purpose of this work was to reveal the relationship between the microbial diversity and flavor profiles of traditional dry-cured duck from a metabolomic perspective. Enterococcus, Psychrobacter, Macrococcus, Salinivbrio, and Staphylococcus were the dominant bacterial genera, while Trichophyton, Kurtzmaniella, Blumeria, Cladosporium, Lysurus, Aspergillus, Starmerella and Debaryomyces were the dominant fungal genera of dry-cured duck. The results showed that aldehydes, alcohols, furan, and ketone compounds were the main volatile flavor compounds of dry-cured duck. Moreover, the identified metabolites of dry-cured duck were classified and included amino acids, amines, polypeptides, amino acid derivatives, polyols, fatty acids, organic acids, flavonoids and isoflavones. Heatmap analysis was used to illuminate the relationships between the microbial diversity and flavor profiles, as well as metabolites. These results will provide an effective theoretical reference for the standardization and modernization of dry-cured duck production.

Inhibition of preadipocyte differentiation and adipogenesis by zinc-α2-glycoprotein treatment in 3T3-L1 cells.

AIMS/INTRODUCTION: Zinc-α2-glycoprotein (ZAG) is associated with the loss of adipose tissue in cancer cachexia, and has recently been proposed to be a candidate factor in the regulation of bodyweight. The aim of the study was to investigate the effects of ZAG on the proliferation and differentiation of 3T3-L1 preadipocytes. MATERIALS AND METHODS: 3-(4,5-Dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) spectrophotometry, Oil Red O staining, intracellular triglyceride assays, real-time quantitative reverse transcription polymerase chain reaction and transient transfection methods were used to explore the action of ZAG. RESULTS: Ectopic ZAG expression significantly stimulates 3T3-L1 cells proliferation in a dose- and time-dependent manner. The maximum influence of ZAG on proliferation was 1.43-fold higher than what was observed in control cells. This effect was observed 144 h after transfection with 0.16 µg of murine ZAG (mZAG) plasmid (P < 0.001). The intracellular lipids content in mZAG over-expressing cells were decreased as much as 37% when compared with the control cells after differentiation (P < 0.05, P < 0.01). The messenger ribonucleic acid levels of peroxisome proliferators-activated receptor-γ (PPARγ), CCAAT enhancer-binding protein-α (C/EBPα) and the critical lipogenic gene, fatty acid synthase (FAS), are also downregulated by up to 50% in fully differentiated ZAG-treated adipocytes. ZAG suppresses FAS messenger ribonucleic acid expression by reducing FAS promoter activity. CONCLUSIONS: Zinc-α2-glycoprotein stimulates the proliferation and inhibits the differentiation of 3T3-L1 murine preadipocytes. The inhibitory action of ZAG on cell differentiation might be a result of the attenuation of the expression of PPARγ, C/EBPα and the lipogenic-specific enzyme FAS by reducing FAS promoter activity.

Effect of long term glucocorticoid treatment on human growth hormone secretion in children and adolescents and the safety and effectiveness of recombinant human growth hormone treatment / 中国医学科学院学报

<p><b>OBJECTIVE</b>Long term glucocorticoid (prednisolone) treatment on human growth hormone (hGH) secretion in children and adolescents and to investigate the effectiveness and safety of the recombinant human growth hormone (rhGH) treatment.</p><p><b>METHODS</b>Twelve patients (age: 10.4∓1.2 years) who were treated in Peking Union Medical College Hospital from September 1999 to November 2009 were enrolled in this study. All of them had taken prednisolone with a dose of 0.5∓2.0 mg/(kg.d) for 6~18 months. Two different hGH stimulating tests was done and their growth and development was evaluated at regular intervals. Seven patients were given rhGH with a dose of 0.1 U/(kg.d) for 6~12 months to improve their growth and development after half a year of prednisolone withdrawal when their disease conditions were improved.</p><p><b>RESULTS</b>The growth speed of these 12 children decreased significantly during prednisolone treatment compared with before prednisolone treatment (1.2∓0.3cm/year vs.3.7∓1.2 cm/year,P12 months than those with a 6~12 months course (P0.05). The growth speed of seven children who received rhGH therapy for half a year were increased from 2.2∓0.1cm/year to 7.8∓0.5cm/year (P<0.05), and then to 6.9∓0.4cm/year one year later.</p><p><b>CONCLUSIONS</b>The long-term glucocorticoid treatment can decrease the hGH secretion, and thus leads to short stature and agenesis. However, the rhGH replacement can safely and effectively improve growth and development in these children after their primary diseases are improved and glucocorticoids are withdrawn.</p>

Fatty acid synthase and hormone-sensitive lipase expression in liver are involved in zinc-alpha2-glycoprotein-induced body fat loss in obese mice.

OBJECTIVE: To explore the effects of zinc-alpha2-glycoprotein (ZAG) on body weight and body fat in high-fat-diet (HFD)-induced obesity in mice and the possible mechanism. METHODS: Thirty-six male mice were fed with standard food (SF) (n = 9) and HFD (n = 27), respectively. Five weeks later, 9 mice fed with HFD were subjected to ZAG expression plasmid DNA transfection by liposome transfection method, and another 9 mice to negative control plasmid transfection. Two weeks later, serum ZAG level in the mice was assayed by Western blot, and the effects of ZAG over-expression on body weight, body fat, serum biochemical indexes, and adipose tissue of obese mice were evaluated. The mRNA expressions of fatty acid synthase (FAS) and hormone-sensitive lipase (HSL) in liver tissue were determined by reverse transcription-polymerase chain reaction. RESULTS: Serum ZAG level significantly lowered in simple HFD-fed mice in comparison to SF-fed mice (0.51 +/- 0.10 AU vs. 0.75 +/- 0.07 AU, P < 0.01). Further statistical analysis demonstrated that ZAG level was negatively correlated with body weight (r = -0.56, P < 0.001), epididymal fat mass (r = -0.67, P < 0.001), percentage of epididymal fat (r = -0.65, P < 0.001), and increased weight (r = -0.57, P < 0.001) in simple SF- and HFD-fed mice. ZAG over-expression in obese mice reduced body weight and the percentage of epididymal fat. Furthermore, FAS mRNA expression decreased (P < 0.01) and HSL mRNA expression increased (P < 0.001) in the liver in ZAG over-expressing mice. CONCLUSIONS: ZAG is closely related to obesity. Serum ZAG level is inversely correlated with body weight and percentage of body fat. The action of ZAG is associated with reduced FAS expression and increased HSL expression in the liver of obese mice.

[Construction of Zinc-alpha2-glycoprotein expression plasmid and its expression in 3t3-l1 preadipocytes].

OBJECTIVE: To construct mouse Zinc-alpha2-glycoprotein (mZAG) eucaryotic expression plasmid and identify its expression in 3T3-L1 preadipocytes. METHODS: The total RNA from mouse liver tissue was extracted. The reverse-transcript(RT)-PCR method was used to amplify the complete domain sequence of mZAG, and the confirmed PCR products was inserted into expression plasmid by DNA ligation. The mZAG expression plasmids with various concentrations (0, 0.4, 0.8, and 1.6 microg) were transfected into 3T3-L1 preadipocytes, and ZAG expression in mRNA and protein level was determined by real-time fluorescence quantitative PCR and Western blot, respectively. RESULTS: DNA sequencing confirmed the right sequence of mZAG expression plasmid pcDNA3.1(-)-mZAG. After the mZAG expression plasmid with different concentrations were transfected into 3T3-L1 preadipocytes, mZAG mRNA level significantly increased and reached 2.58 folds (P=0.002), 3.67 folds (P=0.000 and 5.19 folds (P=0.001) of that in the control group (no mZAG transfection). mZAG protein level also significantly increased and reached 2.75 folds of that in the control group (P=0.017). Treating 3T3-L1 cells with small interfering RNA (siRNA) sequence siRNA 1 and siRNA 4 resulted in a decrease of mZAG mRNA to 49% and 41% of those in the control group(no siRNA sequence transfection) (P=0.002P=0.000)and a decrease of mZAG protein to 55% and 62% of that in the control group (P=0.004,P=0.025). CONCLUSIONS: mZAG expression plasmid pcDNA3.1(-)-mZAG was successfully established in this study. This plasmid can be well expressed in 3T3-L1 preadipocytes. siRNA 1 and siRNA 4 can effectively inhibit the expression of mZAG in these cells.

[Effect of bodyweight on the onset of puberty of female children and adolescents].

OBJECTIVE: To investigate the possible effects and roles of bodyweight on the puberty onset in adolescent girls. METHODS: Totally 288 Chinese female children and adolescent girls aged 5 to 16 were followed up yearly for four consecutive years. The height, bodyweight, fat percentage, sexual characteristics, and the serum levels of leptin and insulin-like growth factor-1 (IGF-1) were studied to analyze the influential factors of puberty onset and age of menarche. RESULTS: The serum level of leptin elevated significantly from age 13 [(9.23 +/- 1.25) microg/L] and reached peak at age 16 [(13.19 +/- 1.45) microg/L]. IGF-1 significantly correlated with the timing of puberty onset (r = 0.292, P = 0.016). BMI and fat percentage had no significant effects on the onset of puberty, but were negatively correlated with the age of menarche (r = -0.323, P = 0.037, r = -0.298, P = 0.038 respectively). CONCLUSION: Bodyweight may have effect on puberty onset in female adolescents.

[Activin inhibits the promoter activity of human growth hormone gene in rat pituitary GH3 cells].

The present study was aimed at investigating the effect of activin on the activity of human growth hormone (hGH) gene promoter in rat pituitary GH3 cells and the underlying molecular mechanism. The method of luciferase reporter gene was used. We firstly established a stable GH3 cell line which contains hGH gene promoter (-484 to 30 bp) and luciferase reporter gene by transfecting pGL3-484-Luc2 luciferase expression plasmid into GH3 cells using Lipofectamine transfection reagent. After treating these cells with activin or activin plus various signaling transduction activators, the concentration of GH in the medium and lysate of GH3 cells and luciferase activities in GH3 cells were measured. The results showed that activin (5 nmol/L, 50 nmol/L) decreased the secretion and synthesis of GH. The amounts of GH content in GH3 lysate and medium treated with 50 nmol/L activin were 82% and 59% of the control, respectively. Furthermore, activin (5, 50 nmol/L) reduced the luciferase expression in stable GH3 cells, with the expression being 77% and 69% of the control (P<0.001). Among the activators of intracellular signaling transduction pathways, mitogen-activated protein kinases kinase (MAPKK/MEK) activators C(6) ceramide (1 micromol/L) abolished completely the inhibitory effect of activin. Western blot analysis further confirmed the inhibition of phosphorylated MEK in GH3 cells. The inhibitory effect of activin was abrogated following the deletion of the fragment from -132 to -66 bp within the hGH gene promoter. These results indicate that activin decreases the activity of hGH gene promoter in rat pituitary GH3 cells. The intracellular MEK dependent signaling pathway and the promoter sequence that spans the -132 to -66 bp fragment of hGH gene are involved in the inhibitory effect of activin.

Mek and p38 MAPK-dependant pathways are involoved in the positive effect of interleukin-6 on human growth hormone gene expression in rat MtT/S somatotroph cells.

OBJECTIVE: To investigate the effect of interleukin-6 (IL-6) on the human growth hormone (hGH) gene expression in a rat somatotropic pituitary cell line MtT/S. METHODS: The plasmids containing various lengths of hGH gene 5'-promoter fragments were constructed. Stably transfected MtT/S cells were created by cotransfecting the above plasmids and pcDNA3. 1(+) with DMRIE-C transfection reagent After the administration of these cells with IL-6 and/or various inhibitors of signaling transduction pathways, the luciferase activities in MtT/S cells lysis were assayed to demonstrate the effects of IL-6 on hGH gene promoter activity and possibly involved mechanism. RESULTS: The 10(3) U/mL IL-6 stimulated GH secretion and synthesis, and promoted the 5'-promoter activity of GH gene in stably transfected MtT/SGL cells with the action of 1.69 times above the control. Among inhibitors of signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 micromol/L) and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 (5 micromol/L) completely blocked the stimulatory effect of IL-6. Western blot analysis further confirmed the activation of phosphorylated MEK and p38 MAPK in MtT/SGL cells. Neither over-expression of Pit-1 nor inhibition of Pit-1 expression affected IL-6 induction of hGH promoter activity. A series of deletion constructs of hGH promoter were created to identify the DNA sequence that mediated the effect of IL-6. The results showed that the stimulatory effect of IL-6 was abolished following deletion of the -196 to - 132 bp fragment. CONCLUSIONS: IL-6 promotes GH secretion and synthesis by rat MtT/S somatotroph cells. The stimulatory effect of IL-6 on hGH gene promoter appears to require the activation of MEK and p38 MAPK, and a fragment of promoter sequence that spans the - 196 to - 132 bp of the gene, but may be unlinked with Pit-1 protein.

Effect of interleukin-1 beta on growth hormone gene expression and its possible molecular mechanism in rat MtT/S somatotroph cells.

OBJECTIVE: To elucidate the effect of interleukin-1 beta (IL-1 beta) on human growth hormone (hGH) gene expression in a rat somatotropic pituitary cell line MtT/S. METHODS: Stably transfected MtT/S cells were firstly established by transfecting 484-Luc1 plasmid which contained hGH gene promoter -484 to +30 bp and luciferase reporter gene. The effect of IL-1 beta on hGH gene expression was determined by assaying the luciferase activities. RT-PCR method was also used to determine whether IL-1 recepor mRNA was expressed in MtT/S cells. RESULTS: The 10(3) U/mL IL-1 beta stimulated secretion and synthesis of GH, and promoted the 5'-promoter activity of GH gene in stably transfected MtT/SGL cells with the action of 1.38 times above the control. Among inhibitors of signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 micromol/L) and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 (5 micromol/L) completely blocked the stimulatory effect of IL-1 beta, and phosphatidylinositol-3-kinase (PI3-K) inhibitor LY294002 partly abolished the effect of IL-1 beta. Western blot analysis further confirmed the activation of phosphorylated MEK and p38 MAPK in MtT/SGL cells. Neither over-expression of Pit-1 nor inhibition of Pit-1 expression affected induction of hGH promoter activity by IL-1 beta. A series of deletion constructs of hGH promoter were created to identify the DNA sequence that mediated the effect of IL-1 beta, and results showed that the stimulatory effect of IL-1 beta was abolished following deletion of the -196 to -132 bp fragment. CONCLUSIONS: IL-1 beta promotes GH secretion and synthesis in rat MtT/S somatotroph cells. The stimulatory effect of IL-1 beta on hGH gene promoter appears to require the activation of MEK, p38 MAPK, PI3-K, and a fragment of promoter sequence that spans the -196 to -132 bp of the gene, but it may be unlinked with Pit-1 protein.

[The survey of puberty timing in healthy boys in Daqing city in northern China].

OBJECTIVE: To investigate the puberty timing in healthy adolescent boys in Daqing city in northern China. METHODS: A cross-sectional and longitudinal combined survey was performed. On 150 male students aged 6-15. Follow up was conducted for 4 years. The serum levels of luteinizing hormone (LH), Follicular Stimulating Hormone (FSH) and total testosterone (TT) were measured. The puberty timing and anthropometry including the body height, weight, and genital development according to Tanner's stages were all recorded. RESULTS: The mean age of puberty onset in healthy adolescent boys is (12.0+/-1.6) years. The growth velocity in the first year after puberty onset is (6.9+/-0.4) cm/year. The level of plasma TT at the time of puberty onset is (1.0+/-0.3) nmol/L. CONCLUSION: The puberty timing of boys in the Daqing city, northern China is in the range from 8 to 14 years.

The regulatory mechanism by which interleukin-6 stimulates GH-gene expression in rat GH3 cells.

The present study was performed to elucidate the effect of interleukin (IL)-6 on the human GH (hGH)-gene expression in GH3 rat pituitary tumor cells using stable transfection of the hGH promoter fused to a luciferase reporter gene. Our results showed that IL-6 (10(2)-10(4) U/ml) stimulated GH secretion and synthesis, and promoted the luciferase expression in stably transfected GH3 cells with the maximal action of 1.99 times above the control by 10(4) U/ml IL-6. Among the inhibitors of signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 microM) and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 (5 microM) completely blocked the stimulatory effect of IL-6. Western blot analysis demonstrated that IL-6 indeed increased the activation of phosphorylated MEK and p38 MAPK in GH3 cells. Neither overexpression of Pit-1 nor inhibiting Pit-1 expression affected IL-6 induction of hGH-promoter activity. To identify the DNA sequence that mediated the effect of IL-6, six deletion constructs of hGH promoter were created. The stimulatory effect of IL-6 was abolished following deletion of the -196 to -132 bp fragment. In conclusion, our data show that IL-6 promotes GH secretion and synthesis by rat pituitary GH3 cells. The stimulatory effect of IL-6 on hGH-gene promoter appears to require the activation of MEK and p38 MAPK, and a fragment of promoter sequence that spans the -196 to -132 bp of the gene, but may be unrelated to Pit-1 protein.

Stimulatory effect of interleukin-1beta on growth hormone gene expression and growth hormone release from rat GH3 cells.

Our previous studies demonstrated that interferon gamma increases the human (h) growth hormone (GH) gene promoter activity in rat pituitary GH3 cells, and its regulatory mechanism may be different from the classical GH-releasing hormone-induced regulatory mechanism. Interleukin-1beta (IL-1beta) is thought to induce the release of GH by pituitary cells, but whether or not and by which mechanisms IL-1beta regulates GH synthesis remains unclear. The purpose of our study was thus to investigate the effect of IL-1beta on the hGH gene expression in GH3 rat pituitary tumor cells using stable transfection of the hGH promoter fused to a luciferase reporter gene. Our results showed that IL-1beta (10-10(4) U/ml) increased GH secretion and synthesis and that 10(2) to 10(4) U/ml IL-1beta promoted the luciferase expression in stable GH3 cells, with a maximal action of 1.61 times over that of controls. Among inhibitors of intracellular signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 microM) and p38 MAPK inhibitor SB203580 (5 microM)blocked completely the stimulatory effect of IL-1beta, and the phosphoinositide 3-kinase inhibitor LY294002 (10 microM) blocked partially the induction of IL-1beta. Western blot analysis demonstrated that IL-1beta increased the activation of phosphorylated MEK and p38 MAPK in GH3 cells. Neither overexpression of Pit-1 nor inhibiting Pit-1 expression affected IL-1beta induction of hGH promoter activity. To identify the DNA sequence that mediated the effect of IL-1beta, six deletion constructs of hGH promoter were created. The stimulatory effect of IL-1beta was abolished following deletion of the -196- to -132-bp fragment. In conclusion, our data show that IL-1beta promotes GH secretion and synthesis by rat pituitary GH3 cells. The stimulatory effect of IL-1beta on the hGH gene promoter appears to require the activation of MEK, p38 MAPK, and phosphoinositide 3-kinase and a fragment of promoter sequence that spans the -196- to -132-bp fragment of the gene, but is unrelated to the Pit-1 protein.

[Puberty development of the healthy adolescent girls of Daqing city, Heilongjiang province].

OBJECTIVE: To investigate the process of puberty development of healthy adolescent girls in Northern China. METHODS: 288 adolescent girls of Daqing city, Heilongjiang province, aged 5 to 16, were studied and followed up yearly for four years. The height, weight, fat percentage, second sex characteristics, and the blood levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E(2)) were examined. RESULTS: The mean age of puberty onset of these healthy adolescent girls was 8.5 years +/- 1.1 years. The blood levels of FSH, LH and E(2) were 0.2 mIU/L, 1.1 mIU/L and 0.06 nmol/L respectively (the 95 percentiles were 2.5 mIU/L, 2.3 mIU/L and 0.12 nmol/L respectively). Their mean age of menarche was 12.4 years +/- 1.2 years. The mean age of breast development was 8.8 years +/- 1.1 years. CONCLUSION: The girls in Northern China begin their puberty development at younger ages than reported before.

[A clinical analysis of 103 male patients with macroprolactinoma].

OBJECTIVE: To explore the clinical characteristics, therapeutic methods and prognostic factors of macroprolactinoma in male patients. METHODS: The clinical data of 103 male patients with macroprolactinoma were retrospectively analyzed. RESULTS: (1) The main symptoms were decreased libido or impotence, headache and hypoplasia. (2) About 57.8% of the patients treated with dopaminergic agonist achieved complete remission, while only 5.7% of the patients achieved complete remission after surgery (chi(2) = 54.148, P < 0.001). Fifty-nine patients who did not completely respond to surgery received other therapeutic methods, including dopaminergic agonist, radiotherapy or combination of them, but no differences were found among these three methods (chi(2) = 3.373, P = 0.498). (3) Patients with invasive tumors had worse prognosis than those with non-invasive tumors; there were no effects of age, duration of the disease, size of tumor, serum prolactin levels or presence of pituitary apoplexy on the prognosis. CONCLUSIONS: Dopaminergic agonist is the treatment of first-choice for male macroprolactinoma. Invasive tumor indicates a poor outcome.

[Mechanism of interleukin-1beta increasing growth hormone expression in rat pituitary GH3 cells].

OBJECTIVE: To investigate the effect(s) of interleukin-1beta (IL-1beta) on the activity of human growth hormone (hGH) gene promoter in rat pituitary GH3 cells and the molecular mechanism. METHODS: The method of luciferase reporter gene was used. We firstly established stable GH3 cell line which contains hGH gene promoter -484-30 bp and luciferase reporter gene. After treating these cells with IL-1beta or IL-1beta plus various signaling transduction inhibitors, the concentration of GH in the medium and lysate of GH3 cells and luciferase activities in GH3 cells were measured to reflect the effect of IL-1beta on secretion and synthesis of GH and the promoter activity of the hGH gene and the molecular mechanism. Results IL-1beta (10-10(4)U/ml) increased secretion and synthesis of GH. IL-1beta at levels of 10(2)-10(4) U/ml promoted the luciferase expression in stable GH3 cells, and the maximal action was 1.61 times of the control (P < 0.001). Among the inhibitors of intracellular signaling transduction pathways, mitogen-activated protein kinases (MAPK) inhibitor PD98059 (40 micromol/L) and p38 MAPK inhibitor SB203580 (5 micromol/L) completely blocked the stimulatory effect of IL-1beta, and phosphoinositide 3-kinase (PI3-K) inhibitor LY294002 (10 micromol/L) partly blocked the induction of IL-1beta. Neither overexpression of Pit-1 nor inhibiting Pit-1 expression affected IL-1beta induction of hGH promoter activity. The stimulatory effect of IL-1beta was abolished following deletion of the -196 to -132 bp fragment. CONCLUSIONS: IL-1beta increases the activity of hGH gene promoter in rat pituitary GH3 cells. This stimulatory effect of IL-1beta appears to require the intracellular MAPK, p38 MAPK, and PI3-K dependent signaling pathways. The effect of IL-1beta requires the promoter sequence that spans the -196 to -132 bp fragment of the gene, but it is unrelated to Pit-1 protein.

[Reduced resistin levels in patients with type 2 diabetes mellitus].

OBJECTIVE: To measure the serum resistin level of patients with type 2 diabetes mellitus so as to examine whether there exists a relationship between resistin, obesity and diabetes. METHODS: ELISA was used to examine the fasting serum resistin, leptin, and true insulin and those 2-hours after taking 75-g glucose in 51 untreated type 2 diabetic patients, 30 males and 21 females, and 52 sex and age-matched normal control subjects. Blood glucose, blood pressure, height, weight, waist circumstance, hip girth were measured. Body mass index (BMI), waist to hip ratio (WHR), and quantitative insulin sensitivity check index (QUICKI) were calculated. RESULTS: In comparison with the control, the diabetic group had higher waist-to-hip ratio (WHR) and serum insulin levels (P < 0.05), but significantly lower resistin levels both in the fasting status (23 ng/ml +/- 15 ng/ml vs 30 ng/ml +/- 18 ng/ml, P < 0.05) and 2 hours after glucose loading (22 ng/ml +/- 11 ng/ml vs 31 ng/ml +/- 15 ng/ml, P < 0.001). The leptin level was not statistically different between the two groups (P > 0.05). The resistin level 2 hours after glucose loading was not significantly different between these 2 groups. Correlation analysis demonstrated that fasting resistin level was not correlated with sex, BMI, leptin, and blood pressure, but positively correlated with QUICKI (r = 0.30, P < 0.01) and negatively correlated with blood glucose (r = -0.21, P < 0.05). CONCLUSION: The serum resistin level of patients with type 2 diabetes is reduced rather than increased in fasting status and 2 hours after glucose taking. Resistin may not be the major link between obesity and diabetes in human beings. Since human resistin level is positively correlated with insulin sensitivity, the use of term "resistin", originally for its resistance to insulin, may be somewhat premature.

IFN-gamma increases the hGH gene promoter activity in rat GH3 cells.

AIM: To study the effect(s) of interferon gamma (IFN-gamma) on the activity of human growth hormone (hGH) gene promoter in rat pituitary GH3 cells and the molecular mechanism underlying the effect(s). METHODS: Cell transfection and luciferase reporter gene were used. RESULTS: IFN-gamma (10(2) and 10(3) U/ml) increased the activity of hGH in GH3 cells. The addition of the mitogen-activated protein kinase inhibitor PD98059 (40 micromol/l) to the cells blocked the stimulatory effect of IFN-gamma. Neither overexpression of Pit-1 nor inhibiting Pit-1 expression affected IFN-gamma induction of hGH promoter activity. To identify the DNA sequence that mediated the effect of IFN-gamma, four deletion constructs of hGH gene promoter were created. The stimulatory effect of IFN-gamma was abolished following deletion of the -250 to -132 fragment. CONCLUSIONS: IFN-gamma increases the activity of hGH gene promoter in rat pituitary GH3 cells. This stimulatory effect of IFN-gamma appears to require the intracellular mitogen-activated protein kinase-dependent signaling pathway. The effect of IFN-gamma requires the promoter sequence that spans the -250 to -132 fragment of the gene, but is unrelated to Pit-1 protein.

[The Effect of Cytokines on Expression of Growth Hormone Gene in Rat Pituitary GH(3) Cells].

To study the effect of interleukin-11(IL-11), ciliary neurotropic factor (CNTF) and transforming growth factor-beta (TGF-beta) on the hGH gene promoter activity in rat pituitary GH(3) cells and the interaction with pituitary-specific transcription factor Pit-1, firstly the stable transformed GH(3) cell line which contained hGH gene promoter 484-30 bp and luciferase reporter gene was established, then the concentration of GH in the medium and lysate of GH(3) cells and luciferase activities in GH(3) cells were measured, after treating these cells with the above cytokines, the effects of cytokines on secretion and synthesis of GH, and the promoter activity of the hGH gene were observed. The results of our experiments showed that IL-11(20 nmol/L), CNTF(10 nmol/L) and TGF-beta(5 nmol/L) regulated secretion and synthesis of GH, and the luciferase expression in stable-transformed GH(3) cells. IL-11 and CNTF had a stimulatory effect, whereas TGF-beta had an inhibitory one. Neither overexpression of Pit-1 nor inhibition of Pit-1 expression could affect the regulatory role of these cytokines. In conclusion, IL-11, CNTF and TGF-beta regulated the GH production in pituitary GH(3) cell line by regulating the hGH gene promoter activity, while Pit-1 might not be involved in the roles.

[The mechanism of interferon-gamma increases growth hormone expression in rat pituitary GH(3) cells].

The method of luciferase reporter gene was used to investigate the effect of interferon-gamma (IFN-gamma) on the activity of human growth hormone (hGH) gene promoter in rat pituitary GH(3) cells, to elucidate the post-receptor signal transduction pathway and the key promoter sequence which mediated the action of IFN-gamma. The luciferase expression plasmid pGL(3)-484-Luc containing hGH gene promoter (-484-2 bp) and luciferase reporter gene were transfected alone or cotransfected with pituitary specific transcription factor Pit-1 expression plasmid (PcDNA-Pit-1-cDNA) or Pit-1 antisense oligonucleotide (Pit-1 OND) into rat GH(3) cells. The changes of luciferase expression in the GH(3) cells were determined, after treatment with IFN-gamma or IFN-gamma plus inhibitors of intracellular signaling pathways, to observe the effect of IFN-gamma and these inhibitors on the activity of hGH gene promoter. The various deletion constructs of Luc reporter: pGL(3)-380-Luc, pGL(3)-250-Luc, pGL(3)-132-Luc and pGL(3)-66-Luc, which contained the -380-2 bp, -250-2 bp, -132-2 bp and -66-2 bp sequences of hGH gene promoter, respectively, were transfected into GH(3) cells, then the changes of luciferase expression in the GH(3) cells were assayed, after treatment with IFN-gamma, to find out the key sequence which mediated the action of IFN-gamma. Our results showed that IFN-gamma (10(5) u/L, 10(6) u/L) could increase luciferase expression in GH(3)cells transfected with pGL(3)-484-Luc alone, the maximal action being 131% of the control (P<0.001). Among the inhibitors of intracellular signaling transduction pathways, only mitogen activated protein kinases (MAPK) inhibitor PD98059 (40 micromol/L) could completely blocked the stimulatory effect of IFN-gamma on hGH gene promoter activity. Pit-1 overexpression or inhibited Pit-1 expression, both had no effect on IFN-gamma-induced hGH gene promoter activity. When various deletion constructs of Luc reporter were transfected into GH(3) cells, only pGL(3)380-Luc and pGL(3)250-Luc still responded to IFN-gamma. In conclusion, IFN-gamma could increase the activity of hGH gene promoter in rat pituitary GH(3) cells. This stimulatory effect of IFN-gamma may be associated with the intracellular MAPK signaling pathway and with -252--132 bp sequence in hGH gene promoter, but had no relationship with pituitary specific transcription factor Pit-1.