© Georg Thieme Verlag KG Stuttgart · New York
Enzymatic Prerequisites for ATP Formation from Triose Phosphates in the A2 and B-Cells of the Endocrine Pancreas of the Guinea-Pig[*]
07 January 2009 (online)
Available data on the metabolism of glucose in the islets of Langerhans are concerned essentially with the B-cells, whereas information on the metabolic properties of the glucagon producing A2-cells is very limited. In this investigation the enzymatic capacity for degradation of triose phosphates has been determined by measurements of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase (PGK) and pyruvate kinase (PK) activities in isolated samples of A2, B- and acinar cells. For GAPDH significant differences were obtained between the cell specimens. The A2-cells showed the highest value, while the activity of acinar cells was lower than that of the B-cells. The same pattern was obtained for PK. The activities of this enzyme were, however, generally lower than for GAPDH. For PGK no differences could be detected between the analyzed specimens, but this enzyme showed a higher activity than the other two enzymes in both the endocrine and exocrine pancreas.
The enzymatic capacity for degradation of triose phosphate by the A2-ceIls is high and the activities of the enzymes measured in these cells exceeded those of B-cells and acinar cells.
Isolated A2-Cells - Guinea-Pigs - Pyruvate Kinase - Phosphoglycerate Kinase - Glyceraldehyde-3-Phosphate Dehydrogenase - Glucagon