Histamine incorporation into murine myeloblasts and promyelocytes. Formation of a histamine transport system.
When isolated murine myeloblasts and promyelocytes were treated with 3H-histamine (5 x 10(-7) M) in RPMI-1640 medium supplemented with 20% horse serum at 37 degrees, the radioactivity of these cells increased gradually, reaching a maximum after 6 hr. However, when these progenitor cells were pretreated with unlabeled histamine (5 x 10(-7) M) for 1 hr, subsequent exposure to 3H-histamine caused prompt incorporation, the extent of which was more than 3.8 times that seen in cells which were not pretreated. This acceleration was prevented by simultaneous addition of cycloheximide (4 x 10(-7) M) or actinomycin D (10(-7) M) in the pre-incubation stage. While the microsomal fraction of progenitor cells pretreated with histamine initially yielded a higher binding capacity, that of the plasma membrane fraction rose significantly after 1 hr. Most of the incorporated 3H-histamine was detected as unmetabolized. Non-histone chromatin protein had a higher affinity to 3H-histamine than did the DNA fraction of progenitor cell nuclei. Histamine inhibited myeloperoxidase activity of myeloid progenitor cells selectively and dose-dependently without affecting eosinophil peroxidase. These findings suggest that histamine incorporated into murine myeloblasts and promyelocytes induces the synthesis of a specific protein(s) through interaction with the nucleus, and that these proteins, in turn, may be combined into the cell membrane, where they act as a transport system for histamine incorporation.