Constitutive nitric oxide synthase (cNOS) activity in Langerhans islets from streptozotocin diabetic rats
Autor: | O. L. Catanzaro, Marcelo D. Carattino, M Frontera, T M Fonovich de Schroeder |
---|---|
Jazyk: | angličtina |
Rok vydání: | 1998 |
Předmět: |
Male
medicine.medical_specialty Nitric Oxide Synthase Type III Arginine endocrine system diseases Physiology medicine.medical_treatment Immunology Biophysics Biochemistry streptozotocin Streptozocin Diabetes Mellitus Experimental Nitric oxide Islets of Langerhans chemistry.chemical_compound nitric oxide Internal medicine medicine Citrulline Animals Rats Wistar General Pharmacology Toxicology and Pharmaceutics lcsh:QH301-705.5 Analysis of Variance lcsh:R5-920 biology diabetes nitric oxide synthase General Neuroscience Insulin Cell Biology General Medicine Streptozotocin Enzyme assay Anti-Bacterial Agents Rats Nitric oxide synthase Endocrinology chemistry lcsh:Biology (General) biology.protein Langerhans islets lcsh:Medicine (General) medicine.drug |
Zdroj: | Brazilian Journal of Medical and Biological Research, Vol 31, Iss 5, p 625 (1998) Brazilian Journal of Medical and Biological Research, Volume: 31, Issue: 5, Pages: 625-632, Published: MAY 1998 Brazilian Journal of Medical and Biological Research, Vol 31, Iss 5, Pp 625-632 (1998) Brazilian Journal of Medical and Biological Research v.31 n.5 1998 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC |
Popis: | Nitric oxide synthase activity was measured in Langerhans islets isolated from control and streptozotocin diabetic rats. The activity of the enzyme was linear up to 150 micrograms of protein from control rats and was optimal at 0.1 microM calcium, when it was measured after 45 min of incubation at 37 degrees C in the presence of 200 microM arginine. Specific activity of the enzyme was 25 x 10(-4) nmol [3H]citrulline 45 min-1 mg protein-1. Streptozotocin diabetic rats exhibited less enzyme activity both in total pancreas homogenate and in isolated Langerhans islets when compared to control animals. Nitric oxide synthase activity measured in control and diabetic rats 15 days after the last streptozotocin injection in the second group of animals corresponded only to a constitutive enzyme since it was not inhibited by aminoguanidine in any of the mentioned groups. Hyperglycemia in diabetic rats may be the consequence of impaired insulin release caused at least in part by reduced positive modulation mediated by constitutive nitric oxide synthase activity, which was dramatically reduced in islets severely damaged after streptozotocin treatment. |
Databáze: | OpenAIRE |
Externí odkaz: |