Some effects of glucose and calcium upon the metabolism of kidney slices from adult and newborn rats

Abstract

A stable phosphate buffered medium was devised for use with slices of surviving kidney tissue which, except for its lack of bicarbonate, resembled the mammalian extracellular fluids in composition. In this medium slices of adult rat kidney maintained a constant respiratory rate for 4 hrs. and could be stored for 24 hrs. at 4[degree] without serious loss of respiratory activity. Glucose and Ca were both essential for the steady respiration of slices of adult rat kidney. When either was absent, the respiration fell to about 75% of its initial rate in 4 hrs., and when both were absent,to about 50%. In the presence of glucose and Ca the slices lost about 12.5% of their N during the equilibration period and a similar quantity in the next 4 hrs. In the absence of Ca, they lost the same amount during equilibration, but about twice as much in the next 4 hrs. Glucose alone did not affect the loss of N, though it augmented the N-sparing effect of Ca. In the new medium, containing both glucose and Ca, slices of infant rat kidney showed a persistently lower respiratory rate and lost a smaller proportion of their N.