Anantamongkol Utchariya, Takemura Haruo, Suthiphongchai Tuangporn, Krishnamra Nateetip, Horio Yoshiyuki
Department of Physiology, Faculty of Sciences, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
Biochem Biophys Res Commun. 2007 Jan 12;352(2):537-42. doi: 10.1016/j.bbrc.2006.11.055. Epub 2006 Nov 20.
Regulatory role of prolactin (PRL) on Ca2+ mobilization in human mammary gland cell line MCF-7 was examined. Direct addition of PRL did not affect cytoplasmic Ca2+ concentration ([Ca2+]i); however, treatment with PRL for 24h significantly decreased the peak level and duration time of [Ca2+]i elevation evoked by ATP or thapsigargin (TG). Intracellular Ca2+ release by IP3 or TG in permeablized cells was not decreased after PRL-treatment, indicating that the Ca2+ release was not impaired by PRL treatment. Extracellular Ca2+ entry evoked by ATP or TG was likely to be intact, because entry of extracellular Ba2+ was not affected by PRL treatment. Among Ca2+-ATPases expressed in MCF-7 cells, we found significant increase of secretory pathway Ca2+-ATPase type 2 (SPCA2) mRNA in PRL-treated cells by RT-PCR experiments including quantitative RT-PCR. Knockdown of SPCA2 by siRNA in PRL-treated cells showed similar Ca2+ mobilization to that in PRL-untreated cells. The present results suggest that PRL facilitates Ca2+ transport into Golgi apparatus and may contribute the supply of Ca2+ to milk.
研究了催乳素（PRL）对人乳腺细胞系MCF-7中Ca2+动员的调节作用。直接添加PRL不影响细胞质Ca2+浓度（[Ca2+]i）；然而，用PRL处理24小时可显著降低由ATP或毒胡萝卜素（TG）引起的[Ca2+]i升高的峰值水平和持续时间。PRL处理后，通透细胞中由IP3或TG引起的细胞内Ca2+释放并未减少，这表明PRL处理并未损害Ca2+释放。由ATP或TG引起的细胞外Ca2+内流可能未受影响，因为细胞外Ba2+的内流不受PRL处理的影响。在MCF-7细胞中表达的Ca2+-ATP酶中，通过包括定量RT-PCR在内的RT-PCR实验，我们发现PRL处理的细胞中分泌途径Ca2+-ATP酶2型（SPCA2）mRNA显著增加。在PRL处理的细胞中用siRNA敲低SPCA2显示出与未处理PRL的细胞相似的Ca2+动员。目前的结果表明，PRL促进Ca2+转运到高尔基体中，并可能有助于向乳汁供应Ca2+。
