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

Cutting & McCance b) compared the meta- bolism of slices cut from the kidneys of newborn and adult animals. They found that the respiratory rate of kidney tissue from newborn rats changed little over a period of 2 hr., whilst that of the adult tissue fell off rapidly. Such a decline has often been reported, and Laser acceptedit asa peculiarity of the kidney. Cutting & McCance noted, however, that their slices of adult tissue were visibly dis- integrating after 2 hr., and had often lost 40-50 % of their nitrogen. These slices were immersed in a solution buffered with phosphate at pH 7-4, similar to that described by Krebs It contained no calcium, andhad about eight times the concentration of phosphate found in mammalian extracellular fluids. Cutting also studied the effect of calcium upon the respiration and the loss of nitrogen of kidney slices from adult and newborn calcium would not remain in a solution containing phosphate at pH 7 4, their comparisons in a saline solution buffered with phosphate at pH 6-8 and in bicar-bonate-Ringer The in the calcium, rate was maintained, but was still far from constant.