Nowak R A, Rein M S, Heffner L J, Friedman A J, Tashjian A H
Department of Molecular and Cellular Toxicology, Harvard School of Public Health, Boston, Massachusetts.
J Clin Endocrinol Metab. 1993 May;76(5):1308-13. doi: 10.1210/jcem.76.5.8496322.
Uterine leiomyomas, which are myometrial smooth muscle tumors, secrete PRL. We investigated the actions of several hormones known to stimulate PRL secretion by the pituitary gland or decidua on PRL secretion by leiomyoma-derived smooth muscle cells (SMC) in monolayer culture. Cultures were verified to be SMC by immunostaining for smooth muscle alpha-action and desmin. Hormone treatments were performed in serum-free medium for 72 h. Medium was harvested every 24 h and assayed for PRL. 17 beta-Estradiol, progesterone, TRH, insulin-like growth factor-I, epidermal growth factor, and the GnRH agonist leuprolide did not affect PRL secretion by these SMC. Insulin caused a significant suppression of PRL secretion by 72 h, and this was accompanied by a 64% increase in total cell protein per well, which represented an increase in cell number. Cells were also plated at various densities to determine the effects of cell number on PRL secretion. The amount of PRL secreted per 1000 cells decreased significantly as cell number per well increased. Northern blot analysis identified PRL mRNA in fresh leiomyoma tissue. PRL mRNA in three independent cultures of SMC was then detected by reverse transcription and the polymerase chain reaction. Hybridization occurred only with the expected band of approximately 423 basepairs in size. We conclude that leiomyomas express PRL mRNA in vivo and that leiomyoma-derived SMC in culture continue to express the PRL mRNA and secrete PRL in the absence of ovarian steroids. PRL secretion by SMC in culture appears to be modulated primarily by changes in cell density.
子宫平滑肌瘤是肌层平滑肌肿瘤，可分泌催乳素（PRL）。我们研究了几种已知能刺激垂体或蜕膜分泌PRL的激素对单层培养的平滑肌瘤来源的平滑肌细胞（SMC）分泌PRL的作用。通过对平滑肌α-肌动蛋白和结蛋白进行免疫染色，证实培养的细胞为SMC。激素处理在无血清培养基中进行72小时。每24小时收集培养基并检测PRL。17β-雌二醇、孕酮、促甲状腺激素释放激素（TRH）、胰岛素样生长因子-I、表皮生长因子和促性腺激素释放激素（GnRH）激动剂亮丙瑞林对这些SMC分泌PRL没有影响。胰岛素在72小时时可显著抑制PRL分泌，同时每孔总细胞蛋白增加64%，这代表细胞数量增加。还以不同密度接种细胞，以确定细胞数量对PRL分泌的影响。随着每孔细胞数量增加，每1000个细胞分泌的PRL量显著减少。Northern印迹分析在新鲜平滑肌瘤组织中鉴定出PRL mRNA。然后通过逆转录和聚合酶链反应在三个独立的SMC培养物中检测到PRL mRNA。杂交仅出现预期大小约为423个碱基对的条带。我们得出结论，平滑肌瘤在体内表达PRL mRNA，培养的平滑肌瘤来源的SMC在没有卵巢甾体激素的情况下继续表达PRL mRNA并分泌PRL。培养的SMC分泌PRL似乎主要受细胞密度变化的调节。
