The use of ferricyanide for the electron microscopic demonstration of dehydrogenases in human steroidogenic cells.

The ultrastructural localization of 3 beta hydroxysteroid ferricyanide reductase, glucose-6-phosphate ferricyanide reductase and nicotinamide adenine dinucleotide and reduced form-ferricyanide reductase was investigated in some human steroidogenic tissues (corpus luteum of pregnancy, fetal adrenal gland and testis, adult testis and placenta) using ferricyanide as an electron acceptor. Copper ferrocyanide deposits were readily observed in the mitochondria, in the smooth endoplasmic reticulum profiles and in the cytoplasm. The sites of the various dehydrogenase activities could be visualized by using appropriate incubating media. The precise localization of various reactions in different electron transfer chains was determined by using different ferricyanide concentrations and intermediate electron-carriers such as menadione or exogenous nicotinamide adenine dinucleotide and reduced form-diaphorase. The use of respiratory chain inhibitors such as rotenone or antimycine A confirmed these data.