Intra-Renal Distribution of Glucose-6-Phosphatase: Methodological and Physiological Considerations.

Summary The intra-renal distribution of glucose-6-phosphatase was reinvestigated because of discrepancies in earlier reports on its presence in certain renal cortical structures, and because of its importance as an indicator of which renal cortical structures effect gluconeogenesis. Possible sources of error in previous histochemical studies were first considered, and quantitative histochemical methods were then chosen for the present studies, which avoid these problems. Glucose-6-phosphatase was found in the proximal and distal convoluted tubules and the medullary rays of the dog renal cortex. Its activities in all sub-cortical areas were very small in comparison to those in the cortical areas, which correlates well with other observations on gluco-neogenesis in these tissues. Speculations on the role of gluconeogenesis in renal function must take these observations into account. Renal cortex also appears to be highly suitable tissue for in vitro studies of gluconeogenesis and factors which influence it.