Western blot analysis of crude membrane preparations from U-251 astrocytoma cells revealed major bands between 42–45 and 50 kDa with the rabbit anti-Cter antibody, whereas the human HR serum and the mouse anti-e1 serum failed to give significant signal (data not shown) suggesting that anti-e1 antibodies contained in these sera poorly recognize the linear (denatured and reduced) forms (glycosylated or not) of Kir4.1. This evidence concerns the gene KCNJ10 and astrocytoma (excluding glioblastoma).