Effect of lumenal contents on colonic cell replacement.

Recent studies have shown that the rate of colonic cell renewal can be altered through fasting and refeeding, which produces a marked depression and transient stimulation, respectively. In the present study, the role of physical versus nutritional stimulation in the colonic fasting-refeeding response and the renewal of the functional colonic compartment were evaluated via a nondestructive colonic ligation procedure. The results reported herein suggest that physical stimulation by lumenal factors is in part required to initiate the colonic hyperplasia seen after refeeding. Blood-borne nutritional factors, in the absence of physical stimulation, cannot alone stimulate colonic cell production. Additional evidence is presented which suggests that this physical stimulation may be manifested through the lumenal distension produced by the newly ingested food materials. The results are discussed from the viewpoint of influencing the functional colonic compartment and physiological capacity.