A biphasic response of rats to cobalt
Roginski, E.E.; Mertz, W.
Journal of Nutrition 107(8): 1537-1542
1977
ISSN/ISBN: 0022-3166 PMID: 886393 Document Number: 121766
The addition of Co 0.25, 0.5 and 1.0 mu g/g to the basal diet containing 0.056 mu g/g depressed growth rates of rats progressively with increasing doses; the depression was overcome by increasing the Co supplement to 2 mu g/g and weight gain was even greater with 3 mu g/g. Larger amounts were progressively toxic. Hb concentrations, haematocrits and thyroid retention of intravenously injected sodium iodide were lowest in rats on the diet with Co 1 mu g/g; the opposite was true for fasting serum glucose. The biphasic response to Co is consistent with the hypothesis that Co in low concentrations may have an essential function in the rat, but interaction of Co with a toxic constituent of the diet is not ruled out.