DeVito W J, Avakian C, Stone S, Okulicz W C, Tang K T, Shamgochian M
Division of Endocrinology, University of Massachusetts Medical Center, Worcester 10655, USA.
J Cell Biochem. 1995 Feb;57(2):290-8. doi: 10.1002/jcb.240570213.
Prolactin (PRL) is a potent mitogen in cultured astrocytes. Because one of the major effects of astrocyte proliferation is the expression of inflammatory cytokines, we examined the effect of PRL-induced mitogenesis on the expression of interleukin-1 (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-alpha (TGF-alpha) in cultured astrocytes. Astrocytes were stimulated with PRL or growth hormone (GH), and the expression of cytokines was determined by immunohistochemistry and Western blot analysis. Following incubation of astrocytes with 1 nM PRL for 6 h, strong positive staining of IL-1 alpha and TNF-alpha, but not TGF-alpha, was found. No detectable staining for the above cytokines was found in vehicle, or GH treated astrocytes. When astrocytes were incubated in the presence of 1 nM PRL for 18 h, strong positive staining for IL-1 alpha and TGF-alpha was found. Immunocytochemical analysis of the expression of TNF-alpha and IL-1 alpha in PRL stimulated astrocytes suggested that the expression of IL-1 alpha preceded the expression of TNF-alpha. To confirm this observation, Western blot analyses were performed on extracts from astrocytes incubated with 1 nM PRL in unstimulated astrocytes, IL-1 alpha levels were not detectable. In astrocytes stimulated with 1 nM PRL, expression of IL-1 alpha was clearly detected after 1 h of incubation, and IL-1 alpha levels continued to increase during the course of the experiment (6 h). In contrast, in astrocytes stimulated with 1 nM PRL, an increase in the expression of TNF-alpha was first apparent after 2 h of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)
催乳素（PRL）是培养的星形胶质细胞中的一种强效促有丝分裂原。由于星形胶质细胞增殖的主要作用之一是炎症细胞因子的表达，我们研究了PRL诱导的有丝分裂对培养的星形胶质细胞中白细胞介素-1（IL-1α）、肿瘤坏死因子-α（TNF-α）和转化生长因子-α（TGF-α）表达的影响。用PRL或生长激素（GH）刺激星形胶质细胞，并通过免疫组织化学和蛋白质印迹分析确定细胞因子的表达。将星形胶质细胞与1 nM PRL孵育6小时后，发现IL-1α和TNF-α有强阳性染色，但TGF-α没有。在载体或GH处理的星形胶质细胞中未发现上述细胞因子的可检测染色。当星形胶质细胞在1 nM PRL存在下孵育18小时时，发现IL-1α和TGF-α有强阳性染色。对PRL刺激的星形胶质细胞中TNF-α和IL-1α表达的免疫细胞化学分析表明，IL-1α的表达先于TNF-α的表达。为了证实这一观察结果，对未刺激的星形胶质细胞中与1 nM PRL孵育的星形胶质细胞提取物进行了蛋白质印迹分析，未检测到IL-1α水平。在用1 nM PRL刺激的星形胶质细胞中，孵育1小时后可清楚检测到IL-1α的表达，并且在实验过程中（6小时）IL-1α水平持续增加。相比之下，在用1 nM PRL刺激的星形胶质细胞中，TNF-α表达的增加在孵育2小时后才首次明显。（摘要截短于250字）
