Characterization of NAD-glycohydrolase in rat lymphoid organs.

Rat thymus and thymocytes possess an NAD-glycohydrolase activity lower than spleen and spleen lymphocytes. In all cases, the highest activity (50%) is bound to the nuclei, while that in the soluble fraction is higher (in percent) in the lymphocytes than in the whole organ. Considering that thymus and thymocytes are characterized by a soluble NAD-ase activity higher than in spleen and in spleen lymphocytes, and that lymphocytes in general have a greater soluble than microsomal activity, we interpret these findings are evidence that the soluble NAD-ase is due essentially to T lymphocytes, of which it represents a typical feature.