Evidence for the expression of both the hydrolase and translocase components of hepatic glucose-6-phosphatase in murine pancreatic islets.
Glucose-6-phosphatase (G6Pase) is a multicomponent enzyme system which regulates the catalysis of glucose-6-phosphate (G6P) to glucose and inorganic phosphate. G6Pase can antagonize glucose phosphorylation, a step prerequisite in the regulation of insulin secretion from pancreatic beta cells, and G6Pase activity is increased in islets isolated from animal models of type II diabetes. Using RT-PCR with hepatic G6Pase catalytic subunit primers, we demonstrate that the sizes of amplified products from ob/ob mouse islets are identical to those from liver cDNA. This was confirmed by PCR-based cloning and sequencing of the hepatic G6Pase catalytic subunit open reading frame from islet cDNA. The expression in islets of the G6P transporter, G6PT1, was also demonstrated, suggesting that all of the identified hepatic G6Pase system genes are expressed in pancreatic islets. Finally, the expression of islet-specific G6Pase-related protein (IGRP) in pancreatic islets was confirmed and its expression in liver was also observed.
Goh
Bee-Hoon
BH
The Rolf Luft Center for Diabetes Research, Department of Molecular Medicine, Karolinska Institute, SE-171 76, Stockholm, Sweden.
Efendić
Suad
S
Khan
Akhtar
A
Portwood
Neil
N
D000818:Animals; D017920:Antiporters / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D020134:Catalytic Domain; D002460:Cell Line; D005952:Glucose-6-Phosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007515:Islets of Langerhans / Q000201:enzymology*; D008099:Liver / Q000201:enzymology; D051379:Mice; D008820:Mice, Obese; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D021122:Protein Subunits; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D014158:Transcription, Genetic
D017920:Antiporters; D009004:Monosaccharide Transport Proteins; D021122:Protein Subunits; D011506:Proteins; C503532:Slc37a4 protein, mouse; C111261:glucose 6-phosphate(transporter); D005952:Glucose-6-Phosphatase; C117983:G6pc2 protein, mouse