Effect of the thymus storage factor (TSF) on the blood sugar and insulin level

The rat thymus extract prepared with physiological NaCl solution causes--by its TSF component--an increase of the blood sugar level. After sugar loading in TSF-treated animals, the blood sugar level becomes gradually higher and the insulin secretion diminishes as compared to the control animals. Thymectomy moderates but does not inhibit the TSF decreasing effect on the insulin level. Consequently, TSF primarily causes a decrease of the blood insulin level which correlates with a rise of the blood sugar level.