Effect of leptin on growth hormone secretion and apoptosis of GH3 cells / 生理学报

In order to investigate the effect of leptin on the secretion of rat pituitary adenoma GH3 cell and its mechanisms, we observed the effect of leptin on the growth hormone secretion, proliferation and apoptosis of GH3 cells. The results indicated that leptin at 1, 10, and 100 nmol/L could inhibit the basal growth hormone secretion of GH3 cells in a dose dependent manner (P<0.05). Short-term treatment of leptin (10 nmol/L) for 30 min, 1 and 3 h did not affect basal GH secretion. However, treatment of the GH3 cells with leptin (10 nmol/L) for 1 d or longer resulted in an inhibition of GH secretion (P<0.05). We used MTT method and flow cytometery (FCM) to study the effect of leptin on the proliferation and apoptosis of GH3 cells. We found that leptin inhibited proliferation of GH3 cells with a dose-dependent manner. And leptin reduced the proportion of cells in S phase, increased the proportion of cells in G1, and increased the proportion of GH3 cells in 2 and 4 phase. These results demonstrate that leptin inhibits the basal GH secretion of GH3 cells, which may be due to the inhibition of DNA synthesis and advanced apoptosis of GH3 cells.

Three subtypes expressions of leptin receptor in the rat anterior pituitary and influence of leptin on intracellular free Ca2+ of the rat growth hormone cell / 中国应用生理学杂志

<p><b>AIM</b>To observe the expression of Leptin receptors (OB-R) in male rat anterior pituitary, and study the influence of Leptin on the level of intracellular free Ca2+ ([Ca2+]i) in the cultured growth hormone (GH) cell of male rat pituitary.</p><p><b>METHODS</b>RT-PCR method was used to observe the expression of Leptin receptors (OB-R) in male rat anterior pituitary. We used grade centrifuging method to get growth hormone (GH) cell, and [Ca2+]i in GH cell was examined by laser scanning confocal system.</p><p><b>RESULTS</b>OB-R mRNA were expressed in male rat anterior pituitary, including OB-R (common form), OB-Ra (short form) and OB-Rb (long form). There were about 70% or 80% GH cell by grade centrifuging. Leptin at 10(-8)mol/L could decrease the level intracellular free Ca2+ ([Ca2+]i) in cultured GH cell.</p><p><b>CONCLUSION</b>There are three subtypes of Leptin receptors expressions in male rat anterior pituitary, and Leptin could reduce intracellular free Ca2+ level of GH cell markedly.</p>

Expression of estrogen receptors alpha and beta in human tongue squamous cancer cell and influence of beta-estradiol on the proliferation of tongue cancer cell / 中国应用生理学杂志

<p><b>AIM</b>To observe the expression of estrogen receptors alpha and beta in human tongue squamous cancer line Tca8113 cell, and to study the influence of beta-estradiol (beta-E2) on the proliferation and cell cycle of cultured Tca8113 cell.</p><p><b>METHODS</b>Immunocytochemistry and RT-PCR methods were used to observe the expression of estrogen receptors (ER) in human tongue squamous carcinoma line Tca8113 cell. 3H-TdR incorporation and cell cycle analysis were used to examine the change of proliferation and DNA synthesis of Tca8113 cell.</p><p><b>RESULTS</b>ER-alpha and ER-beta mRNA were expressed in human tongue squamous cancer cell, and the expression of ER-beta was weaker than that of ER-alpha. beta-Estradiol at 10(-8) mol/L - 10(-6) mol/L could increase the proliferation of human tongue squamous carcinoma cell in a dose dependent manner (P < 0.01). beta-E2 (10(-6) mol/L) could increase the proportion of cells in S phase and G2 phase from 23.5% up to 37.7%. The effect of estradiol on the proliferation of cultured human tongue squamous cancer line Tca8113 cell could be inhibited by Tamoxifen.</p><p><b>CONCLUSION</b>There are ER-alpha and ER-beta expression in human tongue squamous cancer line Tca8113 cell, and beta-estradiol promotes the proliferation and cell cycle of cultured human Tca8113 cell.</p>

Effect of tamoxifen on proliferation of cultured breast cancer and cervical carcinoma cell lines / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of tamoxifen on proliferation of human breast cancer Bcap-37 cells and cervical carcinoma HeLa cells and to explore it's possible mechanism.</p><p><b>METHODS</b>The techniques of cell culture, growth curves, flow cytometry and laser scanning confocal microscope were used.</p><p><b>RESULTS</b>Tamoxifen (10(-6) mol/L) shifted the growth curve of Bcap-37 cells downward, and shifted the growth curve of HeLa cells upward. Tamoxifen (10(-8) - 10(-6) mol/L) inhibited the proliferation of Bcap-37 cells in a dose-dependent manner, but stimulated the proliferation of HeLa cells in a dose-dependent manner. Bcap-37 cells appeared apoptosis when treated with tamoxifen (10(-6) mol/L), and the same dose stimulated the proliferation of HeLa cells at GI/S phases. The apoptotic rate of Bcap-37 cells was 97.5%. It blocked G1 phase of HeLa cells from 55.5% to 32.8%, and increased the S phase from 29.0% to 49.4%. Tamoxifen (10(-6) mol/L) also increased the releasing of calcium in Bcap-37 and HeLa cells.</p><p><b>CONCLUSION</b>Tamoxifen can significantly influence the proliferation of breast cancer and cervical carcinoma cells possibly by affecting cell cycle and stimulating the releasing of Ca2+ in the cells.</p>

Expression of interleukin-2 receptors on breast cancer cell line MCF-7 cells / 中国应用生理学杂志

<p><b>AIM</b>To investigate the expression of interleukin-2 receptors (IL-2Rs) on MCF-7 cells, estradiol's regulation of IL-2Rs expression and the influence of IL-2 on the proliferation of MCF-7 cells.</p><p><b>METHODS</b>Immunocytochemistry and flow cytometric analysis were used to investigate the expression of interleukin-2 receptors (IL-2Rs) by using of specific IL-2R polyclonal antibody; MTT method and 3H-TdR incorporation method were used to examine the changes of proliferation of MCF-7 cells.</p><p><b>RESULTS</b>IL-2Ralpha, beta, gamma like immunoreactive substances can be found on MCF-7 cells and the IL-2Rgamma immunostaining was more strong than the other two. Estradiol of 10(-6) mol/L can increase the percentage of immunoreactive cells of IL-2Ralpha, beta and the expression of IL-2Rgamma. Exogenous addition of recombinant IL-2 of 100 U/ml to 1 000 U/ml can significantly increase the proliferation of MCF-7 cells.</p><p><b>CONCLUSION</b>MCF-7 cell can express IL-2R and estradiol can regulate their expression, IL-2 can influence the proliferation of MCF-7 cells.</p>