目的　研究胰腺癌细胞株是否对氟尿嘧啶 ( 5 - FU )具有固有或获得性不敏感。方法　用 SRB方法检测5 - FU对胰腺癌细胞株 As PC- 1、Capan- 1、Mia- Pa Ca- 2、Panc- 1和 T3 M4的毒性作用。结果　 5 - FU对所有胰腺癌细胞株的 IC50 都很高 ,其中 Mia- Pa Ca- 2和 Panc- 1细胞株对 5 - FU最不敏感 ( IC50 =12 ,13 nmol/ L )。即使是在 5 - FU最敏感的 Capan- 1细胞株 ,其 IC50 仍相当高 ( 473 pm ol/ L)。这些细胞株对 5 - FU的 IC50 甚至高出其临床常用剂量给药时血浆药物浓度的 1～ 5 6倍。结论　大多数胰腺癌细胞株对 5 - FU固有不敏感 ,这些发现也许能作为临床上 5 - FU对胰腺癌疗效差的解释之一 Objective To investigate whether pancreatic cancer cell lines are inherently or acquiredly insensitive to 5 - fluorouracil (5 - FU). Methods The toxic effects of 5 - FU on As PC - 1, Capan - 1, Mia - Pa Ca - 2, Panc - 1 and T3 M4 were detected by SRB method. Results The IC50 of 5 - FU was high for all pancreatic cancer cell lines. Mia - Pa Ca - 2 and Panc - 1 cell lines were the least sensitive to 5 - FU (IC50 = 12, 13 nmol / L). Even in the 5 - FU most sensitive Capan-1 cell line, its IC50 is still quite high (473 pm ol / L). The IC50 of these cell lines to 5 - FU was even 1 to 56 times higher than the plasma drug concentration of its clinical common dose. Conclusions Most pancreatic cancer cell lines are inherently insensitive to 5 - FU, and these findings may serve as one of the explanations for the poor efficacy of 5 - FU on pancreatic cancer