Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of physical training on beta-adrenergic-receptor density (Bmax) and adenylate cyclase (AC) activity in soleus muscles (type I) and the deep red portion (type IIa) and superficial white portion (type IIb) of vastus lateralis muscles in diabetic rats were investigated. Rats were rendered diabetic with streptozotocin ([STZ] 45 mg/kg intravenously [IV]) and were either kept sedentary ([SD] n = 12) or submitted to a progressive 10-week treadmill running program ([TD] n = 13). A group of normal sedentary rats served as controls ([SC] n = 13). Plasma glucose levels were increased in SD rats in comparison with SC rats (21.3 +/- 1.4 mmol/L v 7.7 +/- 0.2; mean +/- SE, P < .001), but levels were partially reversed to normal by training (10.7 +/- 1.7; P < .01 v SD). The gastrocnemius nicotinamide adenine dinucleotide (NAD)-isocitrate dehydrogenase (ICDH) activity was significantly increased in TD rats in comparison to SC or SD rats (P < .001). The Bmax and antagonist affinity (Kd) determined with 125iodocyanopindolol (ICYP) were not affected by diabetes in any of the three types of muscle. In type I muscle, TD rats showed a significant 67% increase in Bmax compared with that of SD rats (TD 26.7 +/- 2.0 v SD 16.0 +/- 1.0; P < .001). In type IIa muscle, Bmax was significantly higher by 68% in TD rats as compared with SD rats (TD 16.5 +/- 1.7 v SD 9.8 +/- 0.9 fmol/mg protein; P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Physical training increases beta-adrenoceptor density and adenylate cyclase activity in high-oxidative skeletal muscle of diabetic rats. 133 10

Previous investigations in our laboratory revealed subsensitivity of right ventricular tissue, isolated from one month STZ-diabetic rats, to the inotropic effects of isoproterenol. The present study was concerned with the characterization of this subsensitivity phenomenon. Observations of supersensitivity to methoxamine accompanied by decreased responsiveness to glucagon without a change in responsiveness to forskolin suggested a specific effect of diabetes on pathways involving receptor-mediated activation of adenylate cyclase. Radioligand binding analysis further revealed a specific decrease in the population of the high affinity state of the beta-adrenoceptor. Since the high affinity receptor state is a necessary intermediate for adenylate cyclase activation and enhanced myocardial contractility, it is proposed that the specific decrease in the high affinity population of the beta-adrenoceptor contributes to myocardial subsensitivity to isoproterenol observed in the diabetic animals. It is further proposed that the decrease in receptor population is related to increases in circulating epinephrine levels which were evident in the diabetic animals.
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PMID:Alterations in the myocardial beta-adrenoceptor system of streptozotocin-diabetic rats. 303 70

Male Wistar neonatal rats at age 1.5 days (Streptozotocin [STZ] group 1) and 5 days (STZ group 2) received a subcutaneous injection of 90 mg/kg STZ. After 10 weeks, the rats were subjected to an oral glucose tolerance test (OGTT) (2 g/kg) in a conscious state. The pancreas perfusion experiments were conducted 2 weeks after the OGTT. There was no statistical difference in insulin response between the STZ group 1 and the control group. On the contrary, in the STZ group 2, the plasma glucose response to OGTT showed a typical diabetic pattern, and the plasma insulin response was markedly blunted. In the isolated perfused rat pancreas, the infusion of glucose evoked a biphasic insulin secretion, but the peak insulin levels induced by 16.7 mmol/L glucose in the STZ group 1 were significantly lower than in the controls. We further investigated characteristics of insulin secretion in response to different secretagogues in these animal models using isolated islets. The insulin content of the islets of the STZ group 1 were about one half that of the control group. Insulin secretion in the STZ group 1 was impaired in response to glucose stimulation, but remained normal in response to arginine and forskolin. These results suggest that insulin secretion of non-insulin-dependent diabetes mellitus (NIDDM) rat model is selectively impaired in response to glucose stimulation, possibly due to a disorder of signaling mechanism other than adenylate cyclase.
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PMID:Characteristic features of insulin secretion in the streptozotocin-induced NIDDM rat model. 305 30

1. There is evidence to suggest that adenosine may regulate arterial smooth muscle cell (SMC) growth and proliferation, which is a key event in atherogenesis. This regulation may be mediated via adenylate cyclase. As diabetes is a known risk factor for atherosclerosis, we investigated the growth of aortic SMC from diabetic rats in primary culture and their sensitivity to adenosine and to adenylate cyclase activity. 2. Diabetes was induced with streptozotocin (STZ, 66 mg kg-1, i.p.) Aortic SMC primary cultures were prepared from STZ-diabetic and age-matched rats 5 weeks after the STZ injection. 3. SMC from STZ-diabetic rats grew faster and reached greater densities at confluence than those from non-diabetic animals. 4. Adenosine inhibited growth in both control and diabetic SMC. However, cells from STZ-diabetic rats were apparently more sensitive to adenosine. 5. Direct activation of adenylate cyclase by forskolin induced a dose-dependent growth inhibition, similar in both groups of cells. 6. Cholera toxin, an activator of stimulatory GTP-binding protein (Gs), induced a similar growth inhibitory response in non-diabetic and diabetic SMC. Pertussis toxin (PTX), an inactivator of inhibitory GTP-binding protein (Gi), did not itself affect SMC growth. However, PTX increased dose-dependently the growth inhibition induced by adenosine in SMC from non-diabetic rats but not in SMC from diabetic rats. 7. These findings suggest a functional abnormality in Gi activity in SMC from diabetic rats, that would explain the increased sensitivity to the nucleoside. This impaired inhibitory pathway may reflect changes in the growth regulation of SMC in experimental diabetic states.
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PMID:Adenosine inhibitory effect on enhanced growth of aortic smooth muscle cells from streptozotocin-induced diabetic rats. 876 8

The changes in beta-adrenergic receptors and in adenylate cyclase (AC) activity were investigated in parotid glands from rats with acute diabetic mellitus (DM) induced by a single injection of streptozotocin (STZ, 80 mg/kg). The animals were divided into three groups: control rats, DM rats, and insulin-treated DM rats. Experiments were performed 7 days after the injection of STZ. Amylase and norepinephrine (NE) contents in parotid glands were markedly decreased in DM rats in comparison with control rats. The density of beta-adrenergic receptor decreased in DM rats, but its affinity for ligand was unaffected. The effect of GTP on isoprenaline (ISO)-stimulated adenylate cyclase (AC) activity significantly decreased in DM rats, but forskolin-stimulated AC activity was unaltered. In addition, diabetes induced the blunted response of AC activity to ISO. The changes in AC activity and in amylase content induced by diabetes were restored by insulin, but those in NE content and receptor density could not. These observations indicate that diabetes decreases NE and amylase contents, receptor density, and receptor-AC coupling in parotid gland, and that these changes would occur in the earlier stage of acute STZ-induced diabetic state.
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PMID:Beta-adrenergic receptors and adenylate cyclase activity in the parotid acinar cells from acute streptozotocin-induced diabetic rats. 1148 85

Dysregulated glucagon drives hyperfunction in hepatic glucose output, which is the main cause of persistent hyperglycemia in type 2 diabetes. Berberine (Zhang et al., 2010) has been used as a hypoglycemic agent, yet the mechanism by which BBR inhibits hepatic gluconeogenesis remains incompletely understood. In this study, we treated diabetic mice with BBR, tested blood glucose levels, and then performed insulin, glucose lactate, and glucagon tolerance tests. Intracellular cAMP levels in hepatocytes were determined by ELISA, hepatic gluconeogenetic genes were assayed by RT-qPCR, and the phosphorylation of CREB, which is the transcriptional factor controlling the expression of gluconeogenetic genes, was detected by western blot. BBR reduced blood glucose levels, improved insulin and glucose tolerance, and suppressed lactate- and glucagon-induced hepatic gluconeogenesis in ob/ob and STZ-induced diabetic mice. Importantly, BBR blunted glucagon-induced glucose production and gluconeogenic gene expression in hepatocytes, presumably through reducing cAMP, which resulted in the phosphorylation of CREB. By utilizing a cAMP analogue, adenylate cyclase (AC), to activate cAMP synthetase, and an inhibitor of the cAMP degradative enzyme, phosphodiesterase (PDE), we revealed that BBR accelerates intracellular cAMP degradation. BBR reduces the intracellular cAMP level by activating PDE, thus blocking activation of downstream CREB and eventually downregulating gluconeogenic genes to restrain hepatic glucose production.
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PMID:Berberine Attenuates Hyperglycemia by Inhibiting the Hepatic Glucagon Pathway in Diabetic Mice. 3197 31