1. Active Transport and Na^+, K^+-ATPase in Herbivorous Voles
(a)Active transport : Radioisotope ^<42>K produced by ^<42>Ar-^<42>K generator was orally injected into the voles. After 30 to 60 minutes. the ^<42>K was absorbed mainly from the forestomach and duodenum. The potassium ion was taken into the liver, kidney, heart and adipose tissues, but the uptake activities for ^<42>K were highest in the liver.
(b)Na^+,K^+-ATPase : Na^+, K^+-ATPase activity was investigated in plasma membrane rich fractions from erythrocytes, liver, kidney and skeletal muscle of herbivorous voles. The activity of the ATPase in kidney was higher than those of other tissues. However, the Na^+,K^+-ATPase activities in plasma membranes of kidney in severe diabetic voles were lower than those in normal cases.
2. Hepatic Glycolytic Enzyme and Lipogenic Enzyme Activities in Voles and Mice
(a)Hepatic glycolytic enzyme : Hepatic glycolytic key enzyme, glucokinase in voles were considerablly lower than that in mice. In the monosodium aspartate (MSA)-treated voles, diabetes was induced. In the slight diabetic cases. the glucokinase activities increased about twice, but in the severe diabetic cases. the enzyme activities decreased about half.
(b)Hepatic lipogenic enzymes : Hepatic ATP citrate lyase an acetyl-CoA Carboxylase in voles were considerably lower than those in mice. In the MSA-treated voles and mice, the plasma insulin concentrations increased significantly. The MSA-treated mice showed remarkably obesity and increase of the lipogenic enzyme activities. In the MSA-treated voles, signs of obesity were not observed and hepatic ATP citrate lyase activity increased significantly, but acetyl-CoA carboxylase activity did not increase.