Age-related augmentation of phosphorylase b kinase in hepatic tissue from the glycogen-storage-disease (gsd/gsd) rat.
The effects of food deprivation on body weight, liver weight, hepatic glycogen content, glycogenolytic enzymes and blood metabolites were compared in young and old phosphorylase b kinase-deficient (gsd/gsd) rats. Although the concentration of glycogen in liver from 9-week-old female gsd/gsd rats (730 mumol of glucose equivalents/g wet wt.) was increased by 7-8% during starvation, total hepatic glycogen was decreased by 12% after 24 h without food. In 12-month-old male gsd/gsd rats the concentration of liver glycogen (585 mumol of glucose equiv./g wet wt.) was decreased by 16% and total hepatic glycogen by nearly 40% after food deprivation for 24 h. Phosphorylase b kinase and phosphorylase a were present at approx. 10% of the control activities in 9-week-old gsd/gsd rats, but both enzyme activities were increased more than 3-fold in 12-month-old affected rodents. It is concluded that the age-related ability to mobilize hepatic glycogen appears to result from the augmentation of phosphorylase b kinase during maturation of the gsd/gsd rat.
D000375:Aging; D000818:Animals; D001835:Body Weight; D005260:Female; D005508:Food Deprivation / Q000502:physiology; D006008:Glycogen Storage Disease / Q000097:blood / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008112:Liver Glycogen / Q000378:metabolism; D008297:Male; D009929:Organ Size; D010764:Phosphorylase Kinase / Q000378:metabolism*; D010763:Phosphorylase b; D051381:Rats; D011919:Rats, Inbred Strains
D008112:Liver Glycogen; D010763:Phosphorylase b; D010764:Phosphorylase Kinase