An iron requirement for the synchronous progression of colonic cells following fasting and refeeding.

Evidence is presented to show dietary iron to be a major co-factor in the colonic hyperplasia observed following fasting and refeeding. The iron component serves to remove a fasting induced colonic G1 cycle block and produce the resultant synchronous progression of cells through the cycle. Deleting iron from the refed diet results in no colonic hyperplasia and/or synchronous progression of cells. The results are discussed from the viewpoint of colonic steady state cell renewal and as a possible tool for the study of in vivo steady state cell renewal.