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| Vardanega-Peicher,M.; Curi,R.; Pagliarini e Silva,S.; Nascimento,K.F.; Bazotte,R.B.. |
| The responsiveness of glycogen breakdown to cAMP was investigated in isolated perfused liver from male Wistar fed rats (200-220 g) with insulin-induced hypoglycemia. The activation of glycogenolysis by 3 µM cAMP was decreased (P<0.05) in livers from rats with hypoglycemia induced by the administration of insulin or during the direct infusion of insulin into the isolated liver. The direct effect of insulin on glycogen catabolism promoted by 3 µM cAMP occurred as early as 3 min after starting insulin infusion. In contrast, the cAMP agonists resistant to phosphodiesterases, 8Br-cAMP and 6MB-cAMP, used at the same concentration as cAMP, i.e., 3 µM, did not modify the effect of insulin. The data suggest that the decreased hepatic responsiveness of glycogen... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Insulin-induced hypoglycemia; Cyclic AMP; Glycogen breakdown; Liver metabolism. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000100007 |
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| Goldstein,J.; Silberstein,C.; Ibarra,C.. |
| Adenylyl cyclase (AC) isoforms catalyze the synthesis of 3',5'-cyclic AMP from ATP. These isoforms are critically involved in the regulation of gene transcription, metabolism, and ion channel activity among others. Nitric oxide (NO) is a gaseous product whose synthesis from L-arginine is catalyzed by the enzyme NO synthase. It has been well established that NO activates the enzyme guanylyl cyclase, but little has been reported on the effects of NO on other important second messengers, such as AC. In the present study, the effects of sodium nitroprusside (SNP), a nitric oxide-releasing compound, on COS-7 cells transfected with plasmids containing AC types I, II, V and VI were evaluated. Total inhibition (~98.5%) of cAMP production was observed in COS-7... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adenylyl cyclase; Nitric oxide; Sodium nitroprusside; Cyclic AMP; COS-7 cells; Signal transduction. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000200002 |
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