Protein phosphatase type-1 mRNA levels in response to starvation-refeeding and streptozotocin-diabetes.
Levels of the mRNA encoding the catalytic subunit of protein phosphatase type-1 (PP-1cat) were reduced in skeletal muscle but not liver in response to short-term (2h) chow refeeding after prolonged (40h) starvation in the rat. This reduction did not appear to be mediated by insulin per se since streptozotocin-induced diabetes was associated with a reduction in PP-1cat levels in skeletal muscle. It is suggested that glucose levels may be one factor that modulates skeletal muscle PP-1cat mRNA levels. Despite the changes in PP-1cat mRNA levels in skeletal muscle, total protein phosphatase-1 catalytic activity was not altered by either chow refeeding or streptozotocin-diabetes. By contrast, although total hepatic PP-1cat mRNA levels were not altered in response to chow refeeding, there was a marked reduction in glycogen phosphorylase phosphatase activity in the cytosol but not in the glycogen/microsomal fraction.
Drake
P G
PG
Department of Biochemistry, University of Western Australia, Perth.
Palmer
T N
TN
D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D004195:Disease Models, Animal; D015870:Gene Expression; D007328:Insulin / Q000097:blood / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000378:metabolism*; D010765:Phosphorylase Phosphatase / Q000378:metabolism; D054645:Protein Phosphatase 1; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013217:Starvation; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D012333:RNA, Messenger; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D010765:Phosphorylase Phosphatase