Intranephron distribution of creatine content in rats.

Creatine is a high energy phosphate donor and play an important role not only in muscle contraction, but also in buffering intracellular energy storage. In this study, we have identified the creatine content in microdissected nephron segments with an ultramicromethod. All nephron segments tested contained creatine, however the distribution was not uniform. Glomerulus, cortical thick ascending limb of Henle's loop and distal tubule possessed comparatively large amounts of creatine when calculated as pM/micrograms tissue protein. When calculation was made as pM/mm tubule length, the first segment of the proximal tubule and the distal tubule were the highest. These results suggest the existence of heterogeneity in creatine content along the nephron as one of the biochemical characteristics in individual nephron segments.