Decrease of nitric oxide synthase in the cerebrocortex of streptozotocin-induced diabetic rats

• Published in: Neuroscience letters 1999-09, Vol.272 (2), p.99-102
• Main Authors: YU, W.-J, JUANG, S.-W, CHIN, W.-T, CHI, T.-C, WU, T.-J, CHENG, J.-T
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blotting, Northern; Cerebral Cortex - enzymology; Diabetes Mellitus, Experimental - genetics; Diabetes Mellitus, Experimental - metabolism; Diabetes Mellitus, Type 1 - metabolism; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Gene Expression Regulation, Enzymologic; Male; Medical sciences; Nitric Oxide Synthase - genetics; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Rats; Rats, Wistar; RNA, Messenger
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(99)00590-X

In an attempt to know the role of nitric oxide in the disease of insulin-dependent diabetic mellitus (IDDM), the present study examined the change of nitric oxide synthase (NOS) both the activity and gene expression in cerebrocortex of streptozotocin-induced diabetic rats (STZ-diabetic rats). The activity of NOS determined by conversion of [3H] L-arginine to [3H] L-citrulline was markedly decreased in STZ-diabetic rats. Northern blot showed that STZ-diabetic rats expressed a lower mRNA level of neuronal NOS (nNOS). Western blot showed a similar decrease of nNOS in STZ-diabetic rats. However, the NOS activity was increased in rats receiving repeated supply of glucose named glucose-challenged rats. Although the mRNA level of nNOS was not changed in the glucose-challenged rats, the immunoblot of nNOS was also decreased in glucose-challenged rats. These findings suggested that NOS was lowered in the brain of STZ-diabetic rats in a way unrelated to the increase of glucose.