scholarly journals Short-term regulation of glycolysis by vasoactive intestinal peptide in epithelial cells isolated from rat small intestine

1989 ◽  
Vol 262 (2) ◽  
pp. 397-402 ◽  
Author(s):  
I Rossi ◽  
L Monge ◽  
J E Feliu
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Cyclic Amp ◽  
Vasoactive Intestinal Peptide ◽  
Glucose Consumption ◽  
Rat Small Intestine ◽  
Glucose Accumulation ◽  
Lactate Formation ◽  
Partial Inactivation ◽  
Rat Enterocytes

In epithelial cells isolated from rat small intestine, we have studied the influence of vasoactive intestinal peptide (VIP), a neurotransmitter which markedly increases enterocyte cyclic AMP, and of two cyclic AMP analogues (8-bromo cyclic AMP and N6,2′-O-dibutyryl cyclic AMP) on the rate of glycolysis, fructose 2,6-bisphosphate concentration and 6-phosphofructo-2-kinase activity, as well as on the rate of 3-O-methyl-D-[14C]glucose uptake. Our results show that, without affecting the rate of 3-O-methyl-D-[14C]glucose accumulation, VIP and cyclic AMP analogues were able to inhibit glucose consumption and L-lactate formation by isolated rat enterocytes. These effects occurred parallel to a significant decrease in the cellular concentration of fructose 2,6-bisphosphate and to a partial inactivation of 6-phosphofructo-2-kinase. These findings support the hypothesis that VIP inhibits glycolysis in rat enterocytes through a cyclic AMP-dependent mechanism.

Apolipoprotein A-IV synthesis in rat intestine: regulation by dietary triglyceride

1987 ◽  
Vol 252 (5) ◽  
pp. G662-G666 ◽  
Author(s):  
T. F. Apfelbaum ◽  
N. O. Davidson ◽  
R. M. Glickman
Keyword(s):  
Protein Synthesis ◽  
Small Intestine ◽  
Total Protein ◽  
Mrna Levels ◽  
Rat Small Intestine ◽  
Rat Intestine ◽  
Apolipoprotein A ◽  
Rat Enterocytes

Apolipoprotein A-IV (apoA-IV) synthesis rates were measured in vivo in rat enterocytes by immunoprecipitation after administration of [3H]leucine into in situ loops of jejunum and ileum. Basal apoA-IV synthesis rates (percent total protein synthesis) were significantly higher in jejunal enterocytes (2.05 +/- 0.54%) compared with ileal enterocytes (0.48 +/- 0.32%) from the same fasted animals. After an acute triglyceride bolus, significant and sustained elevations of apoA-IV synthesis rates were seen in both jejunal and ileal enterocytes with maximal effects noted at 4-6 h. Animals fed diets containing 30% wt/wt triglyceride as saturated (SF) or polyunsaturated (UF) fats for 6 wk had similarly increased rates of apoA-IV synthesis in jejunal enterocytes with both SF (3.73 +/- 0.83%) and UF (3.33 +/- 0.64%) but no change in ileal enterocytes. By contrast, animals consuming a fat-free diet for 3 wk had jejunal apoA-IV synthesis rates indistinguishable from basal values (2.40 +/- 0.45%). Translatable intestinal mRNA levels for pre-apoA-IV after triglyceride increased in parallel to synthesis rates with a 50% increase in jejunum and a 350% increase in ileum observed at 4-6 h. These results suggest that apoA-IV synthesis by rat small intestine increases in response to acute and chronic dietary triglyceride, is maintained in the absence of dietary triglyceride, and may be under pretranslational control.

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