The effect of dietary restriction on thymus autonomy

Fifty percent dietary restriction allows for continued body growth in young animals, whereas in older animals this dietary regime resulted in a 25% drop in body weight over a 10-wk period. This resulted in a relatively low rate of mitosis in the thymus tissue from young animals so that thymus size was maintained in proportion with body weight. There was no evidence to suggest that the thymus glands from dietary restricted young animals could not maintain their role in immune function. In the older animals dietary restriction resulted in depletion of thymic lymphocytes, despite a relatively high rate of cell division. It is postulated that this may be a result of stress caused by the dietary regime.