Biochemical and physiological indicators of mineral status in animals: copper, cobalt and zinc.

The value of estimates of trace element requirements or of data on tissue trace element content for identifying and controlling trace element-related disorders is often limited by inadequate data on the relationships of such criteria to physiological performance. Investigations of metabolic events initiating early pathological responses to deficiency are beginning to suggest more effective indicators of physiologically relevant abnormalities in trace element intake or status. Progress in studies of metabolic responses to deficiencies of copper, cobalt and zinc is reviewed.