Electron microscopic investigation on the zona glomerulosa of rats after treatment with heparin and potassium.

Adrenal zona glomerulosa of rats was investigated by means of electron microscopy after stimulation with potassium and suppression with heparin. Both intreated and control animals two types of mitochondria -- one with tubular and the other with tubulosaccular cristae -- were found. Stimulation with potassium increased the amount of mitochondria with tubular cristae, heparin treatment caused a simplification of the structure of tubulosaccular cristae. It was assumed that these two mitochondrium-poulations contain different enzyme systems, which catalyze the different step-series of aldosterone biosynthesis. On the basis of cytoplasmic density, dark and light cells could be distinguished only in the zona glomerulosa of control rats, they were absent in both groups of treated animals. The density of these cells probably did not depend on their metabolic activity, but rather on their hormone storage.