CALCIUM-ANTAGONISTS INCREASE THE AMOUNT OF MESSENGER-RNA FOR THE LOW-DENSITY-LIPOPROTEIN RECEPTOR IN SKIN FIBROBLASTS

The effects of calcium antagonists on the amount of LDL-receptor (LDL-R) mRNA in cultured human fibroblasts was examined by hybridization with a fragment of LDL-R cDNA. In a 'Northern' blot the fragment hybridized to a 5,3-kilobase RNA, as expected for LDL-R mRNA. The concentration of this RNA was increased in preparations from cells that were treated with Verapamil or Diltiazem. The selectivity of the increase was established by using a probe for beta-actin mRNA. In dot-blot hybridization it was observed that the calcium antagonists cause 2-3-fold relative increase in the amount of LDL-R mRNA. The increase in the amount of LDL-R mRNA is paralleled by elevated high binding and uptake of [125J] LDL by cells pretreated with the calcium entry blocker.