Molybdenum toxicity: interactions between copper, molybdenum and sulphate.

Molybdenum toxicity and the interactions between copper, molybdenum and sulphate are reviewed. The main signs of molybdenum poisoning are poor growth and anaemia (rat, chick, rabbit, cattle and sheep), anorexia (rat), diarrhoea and achromotrichia (cattle and sheep), joint and bone deformities (rat, rabbit, cattle), central nervous system degeneration and loss of crimp in wool (sheep). The following topics are discussed: (1) The effect of sulphate and sulphur compounds on molybdenum toxicity. (2) The effect of molybdenum on tissue copper levels. (3) The effect of molybdenum on the distribution of copper in plasma. (4) The effect of molybdenum on uptake and excretion of copper. (5) The possible existence of copper(II) molybdate in vivo. (6) The influence of molybdenum on sulphide production by ruminal micro-organisms. (7) Competition between molybdenum and sulphate in intestinal transport. (8) Interaction of sulphur with copper in vivo. (9) The possible involvement of molybdenum in gout and multiple sclerosis in humans.