Increase in nitric oxide synthase and NADPH‐diaphorase in the adrenal gland of streptozotocin‐diabetic Wistar rats and its prevention by ganglioside

Levels of nitric oxide synthase (NOS) and NADPH-diaphorase in adrenal glands of streptozotocin-diabetic rats of 8 and 12 weeks' duration compared with control rats were assessed with histo-chemical and biochemical techniques. Adrenal glands from streptozotocin-diabetic rats of 8 weeks' duration treated with ganglioside were examined also. In the adrenal medulla of 8-weeks- and 12-weeks-diabetic rats, NOS-immunoreactive nerve fibres were increased and decreased, respectively; additional NOS-immunoreactive and NADPH-diaphorase stained cells, which appeared to be cortical cells, were located in medulla and cortex compared with controls. Increased intensity in NADPH-diaphorase staining of the cortical cells of diabetic rats was observed also. Ganglioside treatment of the 8-weeks-diabetic rats prevented the diabetic-induced increase in NOS-immunoreactive nerve fibres. Also, it reduced most of the increase in the NOS-immunoreactive and NADPH-diaphorase stained cells and the intensity of NADPH-diaphorase staining of cortical cells. With biochemical assay, a significant increase in NOS activity was found in the adrenal glands from 8-weeks-diabetic rats, and this increase was reduced by ganglioside treatment in four out of six diabetic rats. In summary, streptozotocin-induced diabetes causes an initial increase in the levels of NOS and NADPH-diaphorase in the adrenal gland of rat, which was prevented by ganglioside treatment.