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>

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>

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>