HISTOCHEMICAL STUDIES OF THE CARBOHYDRATE METABOLISM OF THE SUBFORNICAL ORGAN IN THE RAT

The present investigation was designed to study the carbohydrate metabolism of the subfornical organ in detail: The latest histochemical methods were applied to the rat brain. The reactions of the organ were strong for G-6-P and 6-phosphogluconate dehydrogenase, moderate for aldolase, and also moderate for succinate dehydrogenase. The organ showed a moderate to relatively strong reaction for total lactate dehydrogenase. The fast-moving lactate dehydrogenase isozymes were found to be present fairly in it, as well as the slow-moving ones. The reaction was positive for cytochrome oxidase. The parenchymal cells reacted as follows: There were a weak reaction for aldolase, moderate to strong ones for G-6-P and 6-phosphogluconate dehydrogenases, and a moderate to strong one for total lactate dehydrogenase; some cells showed a stronger reaction for slow-moving isozymes (M type) than the reaction for fast-moving isozymes (H type), while the two reactions for isozymes of the other cells are of almost even strength; they showed a moderate cytochrome oxidase reaction. The ependymal cells covering the ventral stalk of the subfornical organ exhibited in strength the similar reactions to those of the parenchymal cells for the enzymes but aldolase, with which they reacted moderately. Weak reactions were observed in the nuclei of the cells for these enzymes