sincalide and 1-9-dideoxyforskolin

In isolated rabbit gastric glands incubated in the presence of 1 mmol/L glucose, the content of fructose 2,6-bisphosphate (F-2,6-P2) was 5.7 +/- 0.5 pmol/mg dry weight. This value was progressively incremented by increasing glucose concentration in the incubation medium, and was almost doubled at 10 mmol/L glucose. Under these conditions, a close correlation could be established between the levels of F-2,6-P2 and the rate of L-lactate formation (r = .98; P less than .05). Both histamine (0.1 mmol/L) and cholecystokinin octapeptide (CCK-OCT; 0.1 mumol/L) increased L-lactate production, without significant changes in either F-2,6-P2 concentration or the amount of 6-phosphofructo-2-kinase in active form. In contrast, forskolin, which markedly increased the glandular content of cyclic adenosine monophosphate (cAMP), partially blocked glucose consumption and caused a significant reduction in both F-2,6-P2 levels and the proportion of 6-phosphofructo-2-kinase in active form. Furthermore, forskolin partially blocked the rate of glucose uptake by isolated gastric glands. Our results suggest a regulatory role of F-2,6-P2 in the control of the glycolytic flux in response to glucose, but not in its response to histamine or CCK-OCT.

Topics: 3-O-Methylglucose; Animals; Colforsin; Cyclic AMP; Fructosediphosphates; Gastric Mucosa; Glucose; Glycolysis; Histamine; In Vitro Techniques; Kinetics; Lactates; Methylglucosides; Pepsinogens; Phosphofructokinase-2; Phosphotransferases; Rabbits; Sincalide