Production of Experimental Polycythemia with Cobalt

Abstract

During a continuation of our studies on nutritional anemia, a polycythemia was observed in rats receiving a certain mixture of metals with Cu as a supplement to a milk-Fe diet, whereas the same mixture of metals without Cu failed to produce this condition. The data are reported together with those from a study of the metals or combination of metals responsible for the polycythemia. Male albino rats, 26 days old, were placed in glass cages and fed whole milk for 4 days. A mixture of Mn, Co, Ni, Zn, Cu, and Fe salts was then added as a supplement to the milk diet 6 days a week. All metals were fed as the same preparations, and at the lower levels, used in our previous work. Weekly hemoglobin determinations showed normal values until the animals were 7 to 9 weeks of age, when a definite increase in hemoglobin occurred. The rats presented an extremely ruddy appearance, and their eyes, ears, and paws became deep red. When it was evident that this was not a transitory condition, hematological studies were made on the animals of this group, as well as on 2 control groups—one receiving the milk diet supplemented by Cu and Fe only, and the other, a normal stock diet. The group averages, based upon 3 determinations at weekly intervals on each rat, may be summarized as follows: The table shows that the animals on the entire mixture of metals exhibited a marked polycythemia, whereas the rats of either control group showed none. The animals showing polycythemia are now 275 days old and the condition has persisted for 30 to 32 weeks. Another group of rats, not reported here, received the mixture of metals without Cu and developed a progressive anemia rather than a polycythemia.