title: Effect of colchicine on guinea pig intrinsic factor-vitamin B12 receptor.
abstract: Colchicine can induce the malabsorption of vitamin B12 and other nutrients. Previous investigations have suggested but not proved that this malabsorption was due to a lesion in the ileal mucosa. Employing the receptor assay of M. Katz and B. A. Cooper (J Clin Invest 54:733-739, 1974), the authors have observed a dose-related, reversible reduction in the quantity of intrinsic factor-vitamin B12 (IF-B12) receptor (from 5.78 ng to 1.3 ng of B12 binding) in the intestinal mucosa of guinea pigs fed 0.05-0.25 mg/100 g colchicine/day for 3 days. Malabsorption of vitamin B12 was also demonstrated in vivo in similarly treated animals. Increasing intestinal motility with cascara sagrada had no effect on the IF-B12 receptor. The quantity of IF-B12 receptor and the amount of vitamin B12 absorbed increased markedly to greater than normal levels during recovery from a 3-day course of colchicine. The total number of intestinal cells decreased after colchicine administration and increased during recovery; however, the fluctuations observed were not sufficient to explain the changes in the quantity of receptor. Histologic examination of the ileal mucosa showed a decrease in the population of villus cells after colchicine. The correlation between the changes in receptor quantity and in vivo B12-absorption prove that the IF-B12 receptor is a critical limiting factor in B12 absorption.
mesh_terms: D000818:Animals; D003078:Colchicine / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism*; D007437:Intrinsic Factor / Q000378:metabolism*; D011955:Receptors, Drug / Q000378:metabolism*; D014805:Vitamin B 12 / Q000378:metabolism*; D014806:Vitamin B 12 Deficiency / Q000139:chemically induced*
chemical_list: D011955:Receptors, Drug; D004247:DNA; D007437:Intrinsic Factor; D014805:Vitamin B 12; D003078:Colchicine