[Long bone growth changes in thymectomized rats in the pre-puberal stage (author's transl)].

The authors studied the relationship between thymus and growth of long bones in rats in the pre-puberal stage. 150 rats of both sexes were divided in 3 groups: thymectomized, sham-thymectomized and controls. The animals were sacrificed 15 days after surgery, the femurs were collected and measured, in length and breadth. Thymectomized animals have a bone growth significantly lesser in length and breadth when compared to the sham-thymectomized animals. The latter ones also presented a lesser bone growth when compared to the controls. The average body weight was also significantly lesser in thymectomized rats than in controls, the same happening with the shamthymectomized rats. It is suggested that the thymus probably presents some kind of relation with the hypothalamus through a positive feed-back, simulating secretion of substances that would act on the adenohypophysis rising the secretion of growth hormone and the thymus playing a role in maintaining the serum levels of growth hormone and thyroxine necessary for the growth and development of bones.