Abstract
Optimal conditions for the determination of succinic dehydrogenase activity in microgram quantities of intact tissue by the method of Defendi and Pearson were studied, and as a consequence certain modifications were found to be advantageous. The improved procedure was compared with that of Jardetzky and Glick which was designed for use on comparable quantities of disrupted tissue. Both procedures gave results in relative agreement with one another, but the former was somewhat simpler, technically, and more sensitive.
The methods were applied to the quantitative histological distribution of the enzyme in the adrenal gland of the steer, and a maximum concentration was observed in the fasciculata with a symmetrical falling off through the zones on both sides to minima in the medulla and capsule. Thus a species difference was noted since earlier work on the rat adrenal showed a maximum in the reticulanis.