Localisation of NADPH-diaphorase-positive structures in the thymus of the rat, mouse and rabbit.

Localisation of the diaphorase activity of nicotinamide adenine dinucleotide phosphate (NADPH-d), acting as a marker of nitric oxide synthesis (NOS), was studied in the thymus of the rat, mouse and rabbit. The NADPH-d-active cells observed in the rat thymus were irregular in shape with numerous projections and were located on the boundary between the cortex and the medulla. The NADPH-d--active cells in the thymus of the mouse were located predominantly in the medulla.