Evaluation of Tetrazolium as a Histochemical Index of Adrenal Cortical Activity.

Abstract

This report is concerned with the application of the tetrazolium technic to a histochemical differentiation of the zonal activity of the various portions of the adrenal cortex. Viable slices of adrenal tissue (1.5 to 2 mm. in thickness) were incubated for 1 hr. at 37.5[degree]C in a 1% solution of 2,3,5-triphenyl tetrazolium chloride (TTC). TTC is a colorless, water soluble compound which is transformed into a red, insoluble formazan by an active enzymatic reduction through intracellular reductases, such as the dehydrogenases. The colored insoluble formazan is deposited in characteristic patterns for each tissue and can be readily identified in frozen sections. The TTC technic has permitted 2 types of evaluation of adrenal cortical activity. First, an overall estimation of the total amt. of reduced TTC was made by photocolorimetric methods. Second, microscopic studies were made of the localization of formazan staining in specific zones of the adrenal cortex under various exptl. conditions. The intracellular deposition of the reduced TTC would appear to reflect closely the. secretory activity of the adrenal cortical cells. Included in the report are expts. with the specific inhibition of TTC deposition in the glomerulosa by DCA, depletion of the adrenal cortex by stress, such as cold and hemorrhage, the acute and chronic effects of ACTH admn., and the progressive development of cortical hypofunction and atrophy as a consequence of hypophysectomy.