Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pharmacokinetics of diclofenac were compared after intravenous and oral administration at a dose of 5 mg/kg in a rat model of diabetes mellitus induced by alloxan (DMIA) or streptozotocin (DMIS), and their respective control rats. Diclofenac was reported to be metabolized via the hepatic microsomal cytochrome P450 (CYP) 2C11 in male rats. The expression and mRNA level of CYP2C11 decreased in rat models of DMIA and DMIS. Hence, the time-averaged nonrenal clearance (Clnr) of diclofenac was expected to be slower in a rat model of diabetes. As expected, after intravenous administration, the Clnr values of diclofenac were significantly slower in rat models of DMIA (11.3 versus 13.6 ml/min/kg) and DMIS (8.06 versus 15.2 ml/min/kg) than those in control rats. As a result, the total area under the plasma concentration-time curve from time zero to time infinity (AUC) values were significantly greater in rat models of DMIA (435 versus 367 microg min/ml) and DMIS (540 versus 329 microg min/ml). However, after oral administration, the AUC from time zero to the last measured time, 12 h, in plasma (AUC0-12 h) values were comparable between the rat models of DMIA and DMIS and their control rats, and this could be due to changes in the first-pass effect of diclofenac and was not due to a decrease in the absorption of diclofenac in the rat models of diabetes.
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PMID:Pharmacokinetics of diclofenac in rat model of diabetes mellitus induced by alloxan or steptozotocin. 1631 11

Glimepiride, a sulfonylurea hypoglycemic agent, is metabolized by cytochrome P450 2C9 (CYP2C9) which is known to have genetic polymorphisms. To examine the effects of CYP2C9 genetic polymorphisms on the safety and efficacy of glimepiride in patients with type 2 diabetes, the responses to the glimepiride were measured in Japanese type 2 diabetic patients with the different CYP2C9 genotype. The reduction in the HbA(1c) was significantly larger (P<0.05) among the CYP2C9*1/*3 subjects than among the CYP2C9*1/*1 subjects. The long-term observations of 2 patients with a CYP2C9*1/*3 suggested that subjects with a CYP2C9*1/*3 respond well to glimepiride during the initial phase of treatment, but 1 patient have shown the weight gain over the long-term treatment. The pharmacokinetic study showed that the area under the concentration-time curve for glimepiride in the CYP2C9*1/*3 subjects was approximately 2.5-fold higher than that of the CYP2C9*1/*1 subjects. The intrinsic clearance of glimepiride by the CYP2C9*3 enzyme was lower than that by the CYP2C9*1 enzyme. These results suggested that the lower hydroxylation activity of glimepiride in the subject with type 2 diabetes and CYP2C9*1/*3 led to a marked elevation in the plasma concentrations of glimepiride and a stronger pharmacological effect of glimepiride.
Diabetes Res Clin Pract 2006 May
PMID:Effect of CYP2C9 genetic polymorphisms on the efficacy and pharmacokinetics of glimepiride in subjects with type 2 diabetes. 1632 95

(1) The first-line treatment for partial epilepsy is carbamazepine monotherapy; gabapentin monotherapy is an alternative, given its lower risk of drug-drug interactions. (2) The standard treatment for neuropathic pain associated with diabetes or post-herpetic neuralgia is a tricyclic antidepressant, with gabapentin as an alternative. Few drugs are available in this setting, and their efficacy is often modest. (3) Pregabalin is a GABA analogue closely related to gabapentin. Both drugs are marketed by Pfizer. Pregabalin has been approved for use in two indications: refractory partial epilepsy and neuropathic pain. (4) In patients with partial epilepsy inadequately controlled by a combination of two or possibly three antiepileptics, three placebo-controlled double-blind trials lasting 12 weeks suggest that adjunctive pregabalin treatment, at a dose of 600 mg/day divided in two or three doses, at least halves the frequency of seizures in 50% of patients. Pregabalin has not been compared with other second-line antiepileptics. (5) In neuropathic pain, there are 12 double-blind placebo-controlled trials involving patients with diabetes or post-herpetic neuralgia. Depending on the trial, between one-third and one-half of patients treated with pregabalin at a dose of 600 mg/day given in two or three doses had at least a 50% reduction in their pain score. In the only trial that included a group treated with amitriptyline (75 mg/day), the latter was significantly more effective than placebo, while pregabalin was not. (6) There are no comparative trials of pregabalin after amitriptyline and gabapentin failure. (7) The adverse effects profile of pregabalin is similar to that of gabapentin, and includes mainly neuropsychological reactions (dizziness and drowsiness). (8) Pregabalin, like gabapentin, can lead to weight gain and peripheral oedema especially in elderly patients. (9) Cases of visual field restriction have been reported with pregabalin in clinical trials. Animal studies suggest a possible risk of haemangiosarcoma, although no human cases have yet been described. (10) Pregabalin, like gabapentin, is eliminated unchanged in urine, implying a limited risk of interactions involving cytochrome P450, and suggesting that the dose should be reduced in patients with even moderate renal failure (creatinine clearance below 60 ml/min). (11) In practice, pregabalin offers nothing new for patients with partial epilepsy, for whom several other antiepileptics are available. The few available treatments for neuropathic pain have limited efficacy, and pregabalin may therefore be tried when both tricyclics and gabapentin fail. However, it is in no way certain that pregabalin is effective in such patients, and comparative trials are lacking.
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PMID:Pregabalin: new drug. Very similar to gabapentin. 1639 76

Erectile dysfunction (ED) is estimated to affect more than 30 million American men and 152 million men worldwide. Therapeutic agents targeting the nitric oxide/cyclic GMP signaling pathway have successfully treated patients with ED; however, the efficacies of these treatments are significantly lower in specific populations such as patients with diabetes. The goal of this study was to discover and identify new endothelium-derived relaxing factors involved in the regulation of erectile function, providing alternative therapeutic targets for treatment of ED. Immunoblotting results showed that protein expressions of epoxygenases from cytochrome P450 (CYP)2B, 2C and 2J subfamilies, as well as NADPH CYP reductase were present in rat corpora cavernosa, which was confirmed by immunohistochemical analysis. Furthermore, CYP2C was localized in cavernosal endothelial cells using double immunolabeling. CYP epoxygenase activity was analyzed by reverse-phase high-pressure liquid chromatography; and the results showed that 11,12- epoxyeicosatrienoic acid (EET) was the major product metabolized by CYP epoxygenases in rat corpora cavernosa. Inhibition of EETs function by injection of an EETs antagonist into rat penis significantly decreased intracavernosal pressure-induced by electrical stimulation of the major pelvic ganglion in vivo. In conclusion, our results suggest that EETs, produced by CYP epoxygenases, in penile endothelial cells serve as vasodilators. Inhibition of this pathway attenuated erectile function, suggesting that EETs are required for normal erection.
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PMID:Cytochrome P450 epoxygenases provide a novel mechanism for penile erection. 1641 8

Microsomal monooxygenases - cytochrome P450 (CYP, EC 1.14.14.1) and flavin-containing monooxygenase (FMO, EC 1.14.13.8) - have profound roles in drug metabolism. While the induction of some metabolic enzymes such as hepatic FMO and intestinal CYP1A, CYP2B is recognized in experimental diabetes, the effect of insulin treatment on FMO and intestinal CYP3A in diabetic animals has not been reported before. Changes in abundance and activity of hepatic and intestinal microsomal CYPs and FMO were studied in streptozotocin-induced diabetic rats either treated or not with insulin. Hepatic FMO1 activity increased in diabetic rats, but it was restored to control value on insulin treatment. Insulin itself had no effect on FMO1 activity in non-diabetic animals. A remarkable increase of total CYP content was accompanied by a reduced CYP3A specific enzyme activity in the small intestine of diabetic animals. The extent of these changes decreased on insulin treatment. Both, hepatic FMO1 and intestinal CYP3A activity correlated with average blood glucose concentration in untreated diabetic rats. These results indicate that insulin is involved in the regulation of hepatic FMO1 and intestinal CYP3A in rats. Blood glucose level is a good marker for FMO induction. The marked reduction of intestinal CYP3A capacity suggests that diabetes exerts a substantial effect on the activity of most determining intestinal CYP enzyme.
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PMID:Insulin in flavin-containing monooxygenase regulation. Flavin-containing monooxygenase and cytochrome P450 activities in experimental diabetes. 1648 20

The large administrative databases of health plans contain information on drug-related medical adverse events (AE) and constitute an increasingly powerful tool for the assessment of drug safety. We conducted a retrospective observational study using an administrative managed care claims database covering 9 million members from diverse regions of the United States. Patients aged >or=18 years who received >or=2 prescriptions for lipid-lowering drugs between July 1, 2000 and December 1, 2004 were included in the study. Hospitalizations with diagnosis codes (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9]) related to muscle, kidney, and liver were determined for patients exposed to 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins), fibrates, extended-release niacin, cholesterol absorption inhibitors, or statin combination therapy. A total of 473,343 patients contributed 490,988 person-years of monotherapy and 11,624 person-years of combination dyslipidemia therapy. Rates of hospitalization due to AEs in patients on monotherapy with currently available statins were similar, whereas the incidence of hospitalization for muscle disorders increased 6.7-fold with cerivastatin therapy. Patients who received a lipid-lowering medication with a concomitant cytochrome P450 3A4 (CYP3A4) inhibitor had a 6-fold increased rate of muscle disorders, including rhabdomyolysis. Hypertension was associated with a 5-fold increase in both muscle and renal events, whereas patients with diabetes mellitus had a 2.5-fold increased risk of renal events. No hospitalized cases of the index AEs were observed in study subjects during the 6-month period before initiation of the lipid-lowering drug. Statin monotherapy as currently prescribed is generally well tolerated and safe.
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PMID:Statin safety: an assessment using an administrative claims database. 1658 31

Ranolazine is a compound that is approved by the US FDA for the treatment of chronic angina pectoris in combination with amlodipine, beta-adrenoceptor antagonists or nitrates, in patients who have not achieved an adequate response with other anti-anginals. The anti-anginal effect of ranolazine does not depend on changes in heart rate or blood pressure. It acts through different pharmacological mechanisms where inhibition of the late inward sodium current (reducing calcium overload and thereby left ventricular diastolic tension) is one plausible mechanism of reduced oxygen consumption. Initial studies used an oral solution or an immediate-release (IR) capsule, but subsequently an extended-release (ER) formulation was developed to allow for twice-daily administration with maintained efficacy. Following administration of an oral solution or IR capsule, peak plasma concentrations (C(max)) are observed within 1 hour. After administration of radiolabelled ranolazine, 73% of the dose was excreted in urine, and unchanged ranolazine accounted for <5% of radioactivity in both urine and faeces. The absolute bioavailability ranges from 35% to 50%. Food has no effect on rate or extent of absorption from the ER formulation. Ranolazine protein binding is about 61-64% over the therapeutic concentration range. Volume of distribution at steady state ranges from 85 to 180 L. Ranolazine is extensively metabolised by cytochrome P450 (CYP) 3A enzymes and, to a lesser extent, by CYP2D6, with approximately 5% excreted renally unchanged. Elimination half-life of ranolazine is 1.4-1.9 hours but is apparently prolonged, on average, to 7 hours for the ER formulation as a result of extended absorption (flip-flop kinetics). Elimination occurs through parallel linear and saturable elimination pathways, where the saturable pathway is related to CYP2D6, which is partly inhibited by ranolazine. Oral plasma clearance diminishes with dose from, on average, 45 L/h at 500 mg twice daily to 33 L/h at 1000 mg twice daily. The departure from dose proportionality for this dose range is modest, with increases in steady-state C(max) and area under plasma concentration-time curve (AUC) from 0 to 12 hours of 2.5- and 2.7-fold, respectively. Ranolazine pharmacokinetics are unaffected by sex, congestive heart failure and diabetes mellitus. AUC increases up to 2-fold with advancing degree of renal impairment. Ranolazine is a weak inhibitor of CYP3A, and increases AUC and C(max) for simvastatin, its metabolites and HMG-CoA reductase inhibitor activity <2-fold. Digoxin AUC is increased 40-60% by ranolazine through P-glycoprotein inhibition. Ranolazine AUC is increased by CYP3A inhibitors ranging from 1.5-fold for diltiazem 180 mg once daily to 3.9-fold for ketoconazole 200 mg twice daily. Verapamil increases ranolazine exposure approximately 2-fold. CYP2D6 inhibition has a negligible effect on ranolazine exposure.
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PMID:Clinical pharmacokinetics of ranolazine. 1664 Apr 53

The nuclear receptor constitutive androstane receptor (CAR), a key transcription factor for the expression of cytochrome P450 (CYP) 2B genes, resides in the cytoplasm under untreated conditions and translocates into the nucleus upon xenobiotic exposure. CAR forms a multiprotein complex including heat shock protein 90 in the cytoplasm as the glucocorticoid receptor, and it is likely that protein phosphatase 2A plays a critical role in the first step of CAR nuclear translocation. In addition to the xenobiotic induction of CYP2Bs, our recent studies have indicated that CAR is important for sex and strain differences and obesity/diabetes-associated changes in the expression of CYP2B genes. These results have raised the hypothesis that the expression of nuclear receptors varies depending on the physiologic condition, leading to the dysregulation of CYP expression. In obese mice fed a high-fat diet, however, hepatic CYP3A levels are drastically decreased without any significant changes in the expression of nuclear receptors including the pregnane X receptor and hepatocyte nuclear factor-4, which are known to be key transcription factors in the expression of CYP3A genes. These results indicate that it is important to investigate the mechanism of the transcriptional regulation of nuclear receptor genes as well as the activation of nuclear receptors to understand the CYP expression system fully.
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PMID:[Roles of nuclear receptors in the gene expression of drug-metabolizing enzymes under various physiological conditions]. 1667 42

Hypertension is often associated with insulin resistance or hyperinsulinemia. Metabolism of arachidonic acid by cytochrome P450 to the vasoconstrictor 20-HETE is thought to be involved in the pathogenesis of hypertension, but the relationship of 20-HETE with insulin resistance is not clearly understood. Obesity is a major determinant of insulin resistance, and we have previously demonstrated a positive relationship between BMI and 20-HETE in untreated hypertensive and normotensive individuals. The present analysis sought to determine if this relationship was related to insulin levels or insulin resistance (HOMA). We analysed 24h urinary excretion of 20-HETE, serum insulin levels and insulin resistance in 66 lean to overweight untreated hypertensive and normotensive individuals. There was a significant positive association between 20-HETE and BMI (p<0.001), and serum insulin and BMI (p=0.003). There were no associations between 20-HETE excretion and either serum insulin or insulin resistance, before or after adjustment for age, gender, BMI and BP, or when hypertensive and normotensive individuals were considered separately. The results of the present study suggest that the observed positive association between urinary 20-HETE excretion and BMI may not be related to circulating insulin levels or insulin resistance.
Diabetes Res Clin Pract 2006 Nov
PMID:20-Hydroxyeicosatetraenoic acid is not associated with circulating insulin in lean to overweight humans. 1671 8

Arachidonic acid metabolites are vital for the proper control of renal haemodynamics and, when not properly controlled, can contribute to renal vascular injury and end-stage renal disease. Three major enzymatic pathways, COX (cyclo-oxygenase), CYP450 (cytochrome P450) and LOX (lipoxygenase), are responsible for the metabolism of arachidonic acid metabolites to bioactive eicosanoids. These eicosanoids can dilate or constrict the renal vasculature and maintain vascular resistance in the face of changing vasoactive hormones. Renal vascular generation of eicosanoids is altered in pathophysiological conditions such as hypertension, diabetes, metabolic syndrome and acute renal failure. Experimental evidence supports the concept that altered eicosanoid metabolism contributes to renal haemodynamic alterations and the development and progression of nephropathy. The possible beneficial renal vascular actions of enzymatic inhibitors, eicosanoid analogues and receptor antagonists have been examined in hypertension, diabetes and metabolic syndrome. This review highlights the roles of renal vascular eicosanoids in the pathogenesis of nephropathy and therapeutic targets for renal disease related to hypertension, diabetes, metabolic syndrome and acute renal failure.
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PMID:Eicosanoids and renal vascular function in diseases. 1676 55


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