NUTRIENT UTILIZATION BY CELLS ISOLATED FROM RAT JEJUNUM, CECUM AND COLON

Cells isolated from the jejunum, cecum and colon of rats were used to study the oxidation of nutrients by quantifying the production of (CO2)-C-14 from 5 mmol/L C-14-labeled exogenous substrate. In colonic cells, the decreasing order of oxidation was as follows: butyrate > acetate > propionate, glucose and glutamine. Acetate and butyrate significantly suppressed oxidation of both glucose and glutamine. In cells taken from the cecum, butyrate was oxidized at a greater rate than all other substrates. Cells taken from the jejunum produced CO2 from exogenous substrates in decreasing order as follows: glutamine > glucose >> acetate, propionate and butyrate. Butyrate oxidation was significantly reduced in colonic cells by 3-hydroxybutyrate, and it was reduced in cecal cells by glucose. Comparisons among the three gut segments showed no differences in glutamine oxidation. Glucose oxidation was greater in cells taken from the colon than from the cecum or jejunum, which were similar. Butyrate and acetate were oxidized at higher rates in cells taken from the cecum and colon than in cells taken from the jejunum, and propionate was oxidized at a greater rate in cells taken from the colon than from the jejunum. These studies demonstrate that relative rates of substrate oxidation differ along the intestinal tract of rats.