Lee S J, Talamantes F, Wilder E, Linzer D I, Nathans D
Howard Hughes Medical Institute Laboratory, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Endocrinology. 1988 May;122(5):1761-8. doi: 10.1210/endo-122-5-1761.
Proliferin (PLF) is a PRL-related glycoprotein secreted by a number of mouse cell lines and by minced mouse placenta. To further investigate the hormone-like characteristics of PLF, we have determined the site of PLF synthesis and storage in the placenta and its concentration in blood serum during pregnancy. By immunohistochemical staining and in situ hybridization PLF protein and messenger RNA (mRNA) were localized to the trophoblastic giant cells. Individual cells contained both PLF and placental lactogen II. Trophoblastic giant cells appear to secrete PLF into the circulation since PLF was found at levels up to 5 micrograms/ml in the serum of pregnant mice by RIA and at somewhat lower concentrations in the amniotic fluid. Moreover, the serum concentration of PLF during pregnancy varied directly with the level of PLF mRNA in the placenta and with the number of placentas per animal. These findings are consistent with the hypothesis that PLF is a placental hormone; its function is not known.
增殖蛋白（PLF）是一种与催乳素相关的糖蛋白，由多种小鼠细胞系和切碎的小鼠胎盘分泌。为了进一步研究PLF的激素样特性，我们确定了PLF在胎盘中的合成和储存部位及其在孕期血清中的浓度。通过免疫组织化学染色和原位杂交，PLF蛋白和信使核糖核酸（mRNA）定位于滋养层巨细胞。单个细胞同时含有PLF和胎盘催乳素II。滋养层巨细胞似乎将PLF分泌到循环系统中，因为通过放射免疫分析发现，怀孕小鼠血清中PLF的水平高达5微克/毫升，而羊水内的浓度略低。此外，孕期PLF的血清浓度与胎盘中PLF mRNA的水平以及每只动物的胎盘数量直接相关。这些发现与PLF是一种胎盘激素的假说相符；其功能尚不清楚。
