Protein metabolism in hepatic tissue of hibernating and arousing ground squirrels.

WHITTEN, BERTWELL K., AND GEORGE J. KLAIN. Protein metabolism in hcpatic tissue of hibernating and arousing ground squirrels. Am. J. Phvsiol. 214(6): 1360-1362. 1968.-Protein metabolism in hepBtic tissue of hibernating, arousing, and normothermic ground squirrels, Citellus tridecemlineatus, was assessed by three methods: 1) measurement of alanine-U-W utilization by liver slices; 2) incorporation of methionine (methyl-W) into protein by microsomal preparations from liver; 3) measurement of arginase activity in liver homogenates. Measurements were made at 6 and 37 C. In comparison to hepatic tissue of normothermic animals: I) protein synthesis from methionine and lipogenesis from alanine were markedly lowered in heparic tissue of hibernating and arousing animals when measured at 37 C, whereas no change was observed at 6 C; 2) incorporation of alanine into hepatic glycogen was increased in hibernating animals at 6 and 37 C. In comparison to hepatic tissue of hibernating animals: I) oxidation of alanine to CO2 was increased in hepatic tissue of arousing and normothermic animals at 6 and 37 C; 2) arginase activity was increased in hepatic tissue of arousing animals at 6 and 37 C and in normothermic animals at 37 C. These data suggested an increased protein catabolism during arousal.