Characterization of columnar absorptive epithelial cells isolated from rat jejunum

The origin and yield of cells isolated from rat jejunum have been assessed; 80-90% of the mature columnar absorptive cells but none of the Paneth, endocrine or regenerating crypt cells were recovered by the methods described. The structural integrity of the isolated cells was tested by phase contrast-, Nomarski interference- and fluorescence light-microscopy; and also by transmission electron microscopy; the isolated cells appeared structurally intact by all microscopic criteria applied. The isolated cells were judged to be functionally intact because they satisfied a number of tests designed to answer three logically related questions, namely: was the cell-surface membrane intact; were the cells able to accumulate selected solutes against a concentration gradient from the exterior medium; and were the cells able to perform biochemical functions which depended upon the integrated activities of several subcellular structures? The isolated cells did retain and accumulate selected solutes, respired at a steady rate on endogenous substrates, showed enhanced respiration on exogenous glucose and glutamine, maintained favourable intracellular proportions of adenine nucleotides (ATP:ADP:AMP), and synthesized cell protein from extracellular amino acids in proportion to the time of incubation. The isolated cells accounted for 80% of the lactic acid produced by intact rat jejunum under similar conditions of incubation.