Histochemical localization of glutaminase I activity in kidney

¹ Department of Pathology, Harvard Medical School, Boston, Massachusetts

A histochemical method is described for the demonstration of glutaminase I in sections of fresh frozen tissue cut in the cryostat. The application of this method to the kidney of the golden hamster revealed extremely high activity of glutaminase I in the papillary collecting ducts, where ammonia is known to appear in the urine. High activities were also present in other segments of the hamster nephron. In the normal and acutely acidotic rat, only slight glutaminase I activity was present in the papillary collecting ducts, although the descending limbs of Henle's loop were quite active. Other segments of the rat nephron, both normal and acidotic, possessed glutaminase I activity. A generalized increase in activity was observed in acidotic animals.