Colchicine selectively inhibits lactase expression by rat enterocytes.

One early aspect of enterocyte differentiation involves the appearance of digestive enzymes in the brush border membrane during cell migration from intestinal crypts onto villi. Present experiments describe how small amounts of colchicine selectively affect this particular aspect of enterocyte development. Oral ingestion of approximately 50 micrograms colchicine per day halves lactase activity in intestinal homogenates without affecting sucrase, maltase or alkaline phosphatase activities. This inhibition, which is completely reversible, takes about 48 hr to become complete. Further analysis of this effect by quantitative cytochemistry shows colchicine to reduce the maximal rate at which lactase activity appears in the brush border membrane. This reduction takes place without substantially affecting enterocyte migration rate or the time taken to fully complete lactase development. The possibility is discussed that small amounts of colchicine can selectively inhibit lactase biosynthesis in both crypt and mature villus enterocytes.