[Tests with human volunteers on parenteral utilization of maltose]

Intravenous infusions of maltose were performed using human volunteers. Four volunteers received maltose in a dose of 0.25 g/kg bodyweight and hour during eight hours. A follow-up period of three hours was added. Six volunteers received maltose in a dose of 0.125 g/kg bodyweight and hour during twelve hours. Only with the lower dose of maltose (0.125 g/kg b.w.) a steady state is reached after six hour continuous infusion. However even under these conditions maltose concentration in blood reaches the high concentration of 70 mg/100 ml. Using the double infusion rate, no steady state is attained when the infusions lasted for eight hours, despite maltose concentration in blood measured 150 mg/100 ml at this time. By measuring different metabolic parameters (fatty acid concentration, phosphate concentration) it is shown that parenterally applicated maltose is metabolized in the human. On the other hand, adverse reactions were not observed. The concentrations of uric acid and bilirubin remain constant and the activity of SGOT is not altered. Renal excretion of sugar measures 25-35% of the maltose administered parenterally. It is concluded that the glucose in urine stems from direct intra tubular hydrolysis of maltose achieved by the neutral maltase of the kidneys. The lack of attaining constant blood concentration for maltose during the infusions and the high renal loss of sugar shows that maltose is not suited as the single substrate for parenteral nutrition. However, there remains the possibility to use maltose in combination with glucose substitutes. The metabolic behaviour of maltose is similar to glucose, it differs from glucose substitutes.