Effect of streptozotocin-diabetes on rat liver asialoglycoprotein receptor turnover: in vivo degradation and in vitro biosynthesis.
The metabolic turnover of the Hepatic Binding Protein (HBP) was investigated in streptozotocin-diabetic rats. We have already shown that diabetes induced a decreased ligand binding capacity while the immunoreactive HBP was normal. To explore the eventual modifications due to diabetic state upon the turnover of HBP, we followed the in vivo degradation of HBP and its biosynthesis in vitro. After in vivo labelling with L-[3H] leucine and purification of HBP from rat livers, we found a 20% decrease in diabetic HBP half-life. By in vitro incubations of freshly isolated hepatocytes and a 2 h-pulse in the presence of L-[35S] methionine, we showed that diabetes provokes an increased uptake of L-[35S] methionine in hepatocytes allowing an augmented synthesis of HBP although the L-[35S] methionine incorporation into total proteins was less efficient.
Couderc
E
E
Laboratoire de Biochemie, UFR des Sciences Pharmaceutiques et Biologiques, Université Paris-Sud, Châtenay-Malabry, France.
Appel
M
M
Slama
A
A
Feger
J
J
D000818:Animals; D037263:Asialoglycoprotein Receptor; D002352:Carrier Proteins / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D006207:Half-Life; D008099:Liver / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013462:Sulfur Radioisotopes; D014316:Tritium
D037263:Asialoglycoprotein Receptor; D002352:Carrier Proteins; D013462:Sulfur Radioisotopes; C027122:hepatic sialoglycoprotein receptor; D014316:Tritium; D008715:Methionine