Leucogenenol a thymothyroid hormone

Thymectomy and, to a lesser extent, thyroidectomy cause a significant decrease in the serum leucogenenol levels of rats. Daily injections of neonatally thymectomized mice with leucogenenol causes the mice to maintain a normal level of neutrophils and lymphocytes in their circulation. The thymus and thyroid are the only tissues in rats and mice that afford radioactive leucogenenol when incubated in a medium containing radioactive D-glucose. It is concluded that the thymus and possibly the thyroid are responsible for the normal biosynthesis of leucogenenol in animals.