抄録
In order to investigate distribution of maltose intravenously administered, a mixture of 10 μCi per kg of 14C-U-maltose and 1 g per kg of 10% maltose solution was injected to normal rabbits. The levels of blood maltose and 14C-maltose rapidly decreased and reached the initial levels within 4 hours. To the contrast, circulating 14C-gluose rose gradually and exceeded 14C-maltose in 90 minutes. In urine, 24% of the total radioactivities excreted was 14C-maltose, 6% being 14C-glucose and 12% other 14C-compounds, respectively. Approximately 10% of total radioactivities was observed in the skeletal muscle 60 minutes after maltose injection, and the radioactivities were measured at different organs in the order of the kidneys, large intestine, liver, small intestine, lungs and heart.
Several experiments were carried out to study on the role played by the kidney in the metabolism of maltose. When maltose was administered to nephrectomized rabbits, 14C-maltose disappeared from blood stream very slowly and increase in 14C-glucose was the smallest. When maltose was injected to the rabbits pretreated with phloridzin, 14C-maltose decreased rapidly in blood and 14C-glucose did not increase. The difference in blood maltose levels in the artery from those in vein across the kidney was widened after maltose had been injected to normal rabbits, whereas blood glucose concentration in the renal vein exceeded that in the renal artery. In phloridzinized rabbits, the A-V difference in maltose was narrower as compared with normal rabbits and blood glucose levels in the renal vein did not exceed those in the artery. When the isolated kidney was perfused for 30 minutes with 0.5% maltose solution, the levels of maltose and glucose in the renal vein rose and not only maltose but also glucose were excreted in urine. Maltose activities in the cortex of the kidney were determined to be 10 times as high as in the medulla.
These results suggest that the kidney plays an important role in the metabolism of maltose intravenously administered. The mechanism as to urinary excretion of glucose after maltose injection was discussed.
