The use of [185W] thiotungstates for tracer studies in secondary hypocuprosis in cattle

[185W] thiotungstates were synthesized in-vitro and purified by techniques developed for thiomolybdates. [185W] trithiotungstate (15 mg W) injected intravenously into cattle was mainly associated with albumin albumin. The presence of the compound in plasma when injected in larger amounts (0.2 to 1 gW) caused an increase in albumin-bound copper and transiently depressed ceruloplasmin diamine oxidase activity. It is suggested that the long-lived, less costly 185W could prove a convenient alternative to 99Mo for tracer studies with labelled thio-compounds in animals.