The influence of nitric oxide synthase inhibitor L-NAME on bones of male rats with streptozotocin-induced diabetes.
The pathophysiological processes underlying the development of diabetic osteopenia has not hitherto been elucidated. Induction of streptozotocin diabetes leads in our experiments to decrease of bone density, ash, mineral content and to thinner cortical width compared to control male rats. In order to investigate the pathogenetic role of bone resorption by osteoclasts in streptozotocin-induced diabetes, we determined the circulating levels of tartrate-resistant acid phosphatase (TRAP), a biochemical marker for bone resorption. Plasma TRAP values in diabetic rats did not differ from their corresponding controls. Streptozotocin diabetes by itself did not have any effect on the weight of seminal vesicles which are highly testosterone-dependent. Low doses of nitric oxide cause bone resorption, but higher doses of NO inhibit bone resorbing activity. We examined the effect of L-NAME (inhibitor of nitric oxide production) after six weeks of administration to diabetic rats. There was no further significant loss of bone mineral density, ash and mineral content or tibia weight in diabetic rats treated with L-NAME. L-NAME itself did not decrease bone metabolism. In our study no evidence of an increased bone resorption was found. Our results have indicated that a predominance of bone resorption over bone formation is not involved in the pathogenesis of diabetes-associated osteopenia. Inhibition of NO neither increased osteoclastic activity (TRAP) nor induced osteopenia in L-NAME-treated rats. This suggests a possibility that NO is not involved in the pathogenesis of diabetic osteopenia.
Broulík
P D
PD
Third Medical Department, First Faculty of Medicine, Charles University, U nemocnice 1, 128 21 Prague 2, Czech Republic. pbrou@cuni.cz
Haluzík
M
M
Skrha
J
J
D000135:Acid Phosphatase / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D001851:Bone Diseases, Metabolic / Q000209:etiology / Q000517:prevention & control; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005269:Femur / Q000737:chemistry / Q000187:drug effects; D006442:Glycated Hemoglobin / Q000032:analysis; D007328:Insulin / Q000097:blood; D007527:Isoenzymes / Q000097:blood; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D012669:Seminal Vesicles / Q000187:drug effects; D000071681:Tartrate-Resistant Acid Phosphatase; D013977:Tibia / Q000737:chemistry / Q000187:drug effects; D016896:Treatment Outcome
D000135:Acid Phosphatase; D001786:Blood Glucose; D004791:Enzyme Inhibitors; D006442:Glycated Hemoglobin; D007328:Insulin; D007527:Isoenzymes; D019331:NG-Nitroarginine Methyl Ester; D019001:Nitric Oxide Synthase; D000071681:Tartrate-Resistant Acid Phosphatase