Yamaguchi M, Ogren L, Endo H, Thordarson G, Kensinger R, Talamantes F
Department of Biology, University of California, Santa Cruz 95064.
Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11396-400. doi: 10.1073/pnas.89.23.11396.
This study was undertaken to determine whether epidermal growth factor (EGF) regulates the secretion of mouse placental lactogen (mPL)-I and mPL-II. Primary cell cultures were prepared from placentas from days 7, 9, and 11 of pregnancy and cultured for up to 5 days. Addition of EGF (20 ng/ml) to the medium resulted in significant stimulation of mPL-I secretion by the second day of culture in cells from days 7 and 9 of pregnancy and significant inhibition of mPL-II secretion by the third or fourth day of culture in cells from days 7, 9, and 11. Dose-response studies carried out with cells from day 7 of pregnancy demonstrated that the minimum concentration of EGF that stimulated mPL-I secretion and inhibited mPL-II secretion was 1.0 ng/ml. EGF did not affect the DNA content of the cells or cell viability, assessed by trypan blue exclusion, nor did it have a general effect on protein synthesis. There are three types of PL-containing giant cells in mouse placental cell cultures: cells that contain either mPL-I or mPL-II and cells that contain both hormones. Immunocytochemical analysis and the reverse hemolytic plaque assay indicated that EGF treatment was accompanied by a significant increase in the number of cells that produce mPL-I, but among the PL cells that contained mPL-I, there was no change in the fraction of cells that contained only mPL-I or the fraction that contained both mPL-I and mPL-II. In contrast, EGF treatment did affect the distribution of mPL-II among PL cells. In control cultures, about 75% of the cells that contained mPL-II also contained mPL-I, but in EGF-treated cultures, all of the cells that contained mPL-II also contained mPL-I. These data suggest that EGF regulates mPL-I and mPL-II secretion at least partly by regulating PL cell differentiation.
本研究旨在确定表皮生长因子（EGF）是否调节小鼠胎盘催乳素（mPL）-I和mPL-II的分泌。从妊娠第7、9和11天的胎盘制备原代细胞培养物，并培养长达5天。在培养基中添加EGF（20 ng/ml）导致妊娠第7和9天的细胞在培养第二天时mPL-I分泌受到显著刺激，而在妊娠第7、9和11天的细胞在培养第三天或第四天时mPL-II分泌受到显著抑制。对妊娠第7天的细胞进行的剂量反应研究表明，刺激mPL-I分泌和抑制mPL-II分泌的EGF最低浓度为1.0 ng/ml。EGF不影响细胞的DNA含量或细胞活力（通过台盼蓝排斥法评估），对蛋白质合成也无普遍影响。小鼠胎盘细胞培养物中有三种含PL的巨细胞：含有mPL-I或mPL-II的细胞以及同时含有两种激素的细胞。免疫细胞化学分析和反向溶血空斑试验表明，EGF处理伴随着产生mPL-I的细胞数量显著增加，但在含有mPL-I的PL细胞中，仅含mPL-I的细胞比例或同时含mPL-I和mPL-II的细胞比例没有变化。相比之下，EGF处理确实影响了mPL-II在PL细胞中的分布。在对照培养物中，约75%含有mPL-II的细胞也含有mPL-I，但在EGF处理的培养物中，所有含有mPL-II的细胞也都含有mPL-I。这些数据表明，EGF至少部分通过调节PL细胞分化来调节mPL-I和mPL-II的分泌。
