Molybdate and tungstate transfer by rat ileum. Competitive inhibition by sulphate

Biochim Biophys Acta. 1976 Dec 14;455(3):937-46. doi: 10.1016/0005-2736(76)90062-6.


For both MoO42- and WO42- the maximum rate of uptake by the small intestine of the rat (studied in vitro using the everted sac technique) occurs in the lower ileum. Kinetic constants, derived by a least squares procedure, are compared with those previously obtained for SO42- transport. For both V and Ka, SO42- greater than MoO42- greater than WO42-, with only small differences between sacs IV and V. Mutual inhibition of MoO42- and WO42- transport and inhibition of both by SO42- are competitive processes. This is shown by the generally good agreement between Ka values and derived Ki values and by V values in the presence and absence of the inhibiting species. The three ions SO42-, MoO42- and WO42- are probably transferred across the intestine by a common carrier system. Implications for the sulphate-molybdenum interaction in molybdosis are discussed.

MeSH terms

  • Animals
  • Binding, Competitive
  • Biological Transport, Active
  • Copper / pharmacology
  • Ileum / drug effects
  • Ileum / metabolism
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / metabolism*
  • Intestine, Small / drug effects
  • Intestine, Small / metabolism*
  • Kinetics
  • Molybdenum / metabolism*
  • Rats
  • Sulfates / pharmacology*
  • Tungsten / metabolism*


  • Sulfates
  • Copper
  • Molybdenum
  • Tungsten