Effects of lithium (Li) deficiency and/or immobilization stress on the
thymus weight and differential blood count of rats were studied. The
thymus weight of the rats fed a low Li diet were lighter than those of
rats fed a Li supplemented diet, whether the rats were exposed to str
ess or not. Of the rats not exposed to stress, those in the low Li die
t group showed a significant decrease in the ratios of neutrophiles an
d T helper lymphocytes. However, there was an increase in the total nu
mber of lymphocytes in the low Li dietary group. It was shown that Li
deficiency altered the responses to stress in rats.