Although extensive investigation has been focused upon the derangements of intermediary metabolism which result from impaired utilization of glucose, relatively little attention has been paid to the physiological consequences of hyperglycemia per se. In this regard, it should be recalled that glucose, as a solute, adds to total osmolality of body water and that it is principally confined to the extracellular fluids. Thus, excessive elevations of plasma glucose should elicit a shift of water from intracellular to extracellular compartments and result in cellular dehydration1-3 unless repair is effected by the stimulation of thirst and the renal conservation of water.
These interrelationships are uniquely challenged in diabetes mellitus. The stresses are mediated not only by the sustained hyperglycemia that characterizes poor regulation, but also by the almost invariable, excessive hyperglycemia that occurs in the immediate postprandial period. Since each change of blood sugar of 18 mg. % also represents a change