When parathyroid glands slices were incubated in Earle′s balanced salt solution with 3H-leucine and various concentrations of the amine buffer, Tris, there was a time- and dose-dependent inhibition in the formation of 3H-PTH. The rate of synthesis of 3H-ProPTH as well as of total protein on the other hand were unaffected. Moreover, the combined amount of radioactivity in ProPTH and PTH remained about the same. Thus it appears that Tris selectively inhibited the conversion of ProPTH to PTH. Among several other aminestested, diethylamine and glycinamide also were inhibitory. Electron microscopy of parathyroid gland tissue which had been incubated in solutions containing the inhibitory amines indicated that there existed a time- and dose-dependent distension of the Golgi complex. Since Tris did not interfere with the conversion of ProPTH to PTH in a cell-free homogenate system, our data suggest that the inhibitory amines blocked the formation of PTH by disrupting the putative conversion site, the Golgi compl...