Yamaguchi M, Kawai M, Kishi K, Miyake A
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Eur J Endocrinol. 1995 Sep;133(3):342-6. doi: 10.1530/eje.0.1330342.
We examined whether epidermal growth factor (EGF), interleukin (IL)-1, IL-6 and cAMP analogs, which regulate mouse placental lactogen II secretion, affect rat placental lactogen (rPL)-II secretion using a rat choriocarcinoma cell line, Rcho-1. EGF, IL-1 and IL-6 did not affect rPL-II secretion, but 8-bromo-cAMP and forskolin inhibited rPL-II secretion by the 8th day of culture. The effects were dose dependent and the lowest concentrations of 8-bromo-cAMP and forskolin that significantly inhibited rPL-II secretion were 125 and 5 mumol/l, respectively. Cholera toxin also inhibited rPL-II secretion. The reverse hemolytic plaque assay for rPL-II indicated that the cells releasing rPL-II in the culture were giant cells and that 8-bromo-cAMP decreased the number of rPL-II-releasing cells. Western blot analysis of rPL-II yielded a single band at approximately 24.5 K, and 8-bromo-cAMP treatment significantly reduced the band intensity. Northern blot analysis of rPL-II indicated that 8-bromo-cAMP also reduced rPL-II gene expression. These findings suggest that the increase of intracellular cAMP accumulation results in inhibition of rPL-II secretion by decreasing rPL-II gene expression and inhibiting giant cell differentiation.
我们使用大鼠绒毛膜癌细胞系Rcho-1，研究了调节小鼠胎盘催乳素II分泌的表皮生长因子（EGF）、白细胞介素（IL）-1、IL-6和cAMP类似物是否会影响大鼠胎盘催乳素（rPL）-II的分泌。EGF、IL-1和IL-6不影响rPL-II的分泌，但在培养的第8天，8-溴-cAMP和福斯可林抑制了rPL-II的分泌。这些作用呈剂量依赖性，显著抑制rPL-II分泌的8-溴-cAMP和福斯可林的最低浓度分别为125和5 μmol/l。霍乱毒素也抑制rPL-II的分泌。针对rPL-II的反向溶血空斑试验表明，培养中释放rPL-II的细胞是巨细胞，且8-溴-cAMP减少了释放rPL-II的细胞数量。rPL-II的蛋白质免疫印迹分析在约24.5 K处产生一条带，8-溴-cAMP处理显著降低了条带强度。rPL-II的Northern印迹分析表明，8-溴-cAMP也降低了rPL-II基因的表达。这些发现提示，细胞内cAMP积累的增加通过降低rPL-II基因表达并抑制巨细胞分化，从而导致rPL-II分泌受到抑制。
