Kullman J, Gisi C, Lowe M E
Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Am J Physiol. 1996 May;270(5 Pt 1):G746-51. doi: 10.1152/ajpgi.1996.270.5.G746.
The pancreas makes two pancreatic proteins [pancreatic lipase-related protein-1 (PLRP-1) and PLRP-2] with marked homology to pancreatic lipase (PL). To determine if a pancreatic acinar cell line, AR42J, also expresses PLRP-1 and PLRP-2, we examined the cells for the presence of PL, PLRP-1, and PLRP-2. RNA blot analysis with specific probes and immunoblot analysis with antipeptide antibodies demonstrated the presence of mRNA and protein for all three homologues in AR42J cells. Additionally, we showed that dexamethasone decreased PLRP-1 mRNA levels twofold and increased PLRP-2 mRNA 20-fold but had little effect on PL or colipase mRNA. Extracellular PLRP-2 protein levels increased threefold, and intracellular PLRP-2 protein levels increased about fourfold. The characteristics of the dexamethasone-induced increase in PLRP-2 mRNA, a rapid change requiring new protein synthesis independent of mRNA turnover, suggested that dexamethasone regulated transcription. We conclude that AR42J cells synthesize and secrete PL, PLRP-1, and PLRP-2 and that dexamethasone discoordinately regulates the expression of the three genes.
胰腺会产生两种与胰脂肪酶（PL）具有显著同源性的胰腺蛋白[胰脂肪酶相关蛋白-1（PLRP-1）和PLRP-2]。为了确定胰腺腺泡细胞系AR42J是否也表达PLRP-1和PLRP-2，我们检测了这些细胞中PL、PLRP-1和PLRP-2的存在情况。用特异性探针进行RNA印迹分析以及用抗肽抗体进行免疫印迹分析表明，AR42J细胞中存在这三种同源物的mRNA和蛋白质。此外，我们发现地塞米松使PLRP-1 mRNA水平降低了两倍，使PLRP-2 mRNA增加了20倍，但对PL或辅脂酶mRNA影响很小。细胞外PLRP-2蛋白水平增加了三倍，细胞内PLRP-2蛋白水平增加了约四倍。地塞米松诱导的PLRP-2 mRNA增加的特征，即一种快速变化，需要新的蛋白质合成且与mRNA周转无关，表明地塞米松调节转录。我们得出结论，AR42J细胞合成并分泌PL、PLRP-1和PLRP-2，并且地塞米松不协调地调节这三个基因的表达。
