Inhibition of some spontaneous secretory processes in macrophages and fibroblasts by ammonium chloride

Ammonium chloride inhibits the spontaneous secretion of lysozyme by mouse macrophages and the murine macrophage-like cell line P388D₁ and the spontaneous secretion of lysosomal enzymes by P388D₁ cells, normal human fibroblasts and the hypersecretory mucolipidosis II (I-cell) fibroblasts. NH⁴Cl can also inhibit protein synthesis, but this is shown to occur mainly at higher concentrations, or after longer periods of exposure, than are needed for the inhibition of the spontaneous secretory processes. It is confirmed that this amine can also interfere with the continuous endocytosis of fluid in the murine cell types. The nature of the inhibitions is discussed.