Novel expression of liver FBPase in Langerhans islets of human and rat pancreas.
Several reports have indicated the absence of gluconeogenic enzymes in pancreatic islet cells. In contrast, here we demonstrate that liver fructose-1,6-bisphosphatase (FBPase) is highly expressed both in human and rat pancreas. Interestingly, pancreatic FBPase is active and functional, and is inhibited by AMP and fructose-2,6-bisphosphate (Fru-2,6-P2). These results suggest that FBPase may participate as a component of a metabolic sensing mechanism present in the pancreas. Immunolocalization analysis showed that FBPase is expressed both in human and rat Langerhans islets, specifically in beta cells. In humans, FBPase was also located in the canaliculus and acinar cells. These results indicate that FBPase coupled with phosphofructokinase (PFK) plays a crucial role in the metabolism of pancreatic islet cells. The demonstration of gluconeogenic recycling of trioses as a new metabolic signaling pathway may contribute to our understanding of the differences between the insulin secretagogues trioses, fructose, and glucose in pancreas.
Yáñez
Alejandro J
AJ
Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
Bertinat
Romina
R
Spichiger
Carlos
C
Carcamo
Juan G
JG
de Los Angeles García
María
M
Concha
Ilona I
II
Nualart
Francisco
F
Slebe
Juan C
JC
D000818:Animals; D006597:Fructose-Bisphosphatase / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007515:Islets of Langerhans / Q000201:enzymology*; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology*; D008297:Male; D009928:Organ Specificity; D051381:Rats
D006597:Fructose-Bisphosphatase