Effect of bodyweight on the onset of puberty of female children and adolescents / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the possible effects and roles of bodyweight on the puberty onset in adolescent girls.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSION</b>Bodyweight may have effect on puberty onset in female adolescents.</p>

Activin inhibits the promoter activity of human growth hormone gene in rat pituitary GH3 cells / 生理学报

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.

Construction of Zinc-alpha2-glycoprotein expression plasmid and its expression in 3t3-l1 preadipocytes / 中国医学科学院学报

<p><b>OBJECTIVE</b>To construct mouse Zinc-alpha2-glycoprotein (mZAG) eucaryotic expression plasmid and identify its expression in 3T3-L1 preadipocytes.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>

Fatty acid synthase and hormone-sensitive lipase expression in liver are involved in zinc-alpha2-glycoprotein-induced body fat loss in obese mice / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

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 / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Effect of interleukin-1 beta on growth hormone gene expression and its possible molecular mechanism in rat MtT/S somatotroph cells / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Mechanism of interleukin-1beta increasing growth hormone expression in rat pituitary GH3 cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

EVALUATION OF ANTERIOR PITUITARY FUNCTION BY COMBINED ADMINISTRATION OF HYPOTHALAMIC RELEASING HORMONE IN PATIENTS WITH IDIOPATHIC GROWTH HORMONE DEFICIENCY / 中华内分泌代谢杂志

0.05), indicating that the functional reserve of PRL, TSH and ACTH cells were normal in IGHD patients. Except the ratio of peak and basal level, all the other five indices of the LH response to LHRH were significantly lower in IGHD patients than in normals of puberty. The functional reserve of LH cell was low in about 2/3 IGHD patients. These results might explain the delayed or no puberty in adult IGHD patients.