Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study assessed the synergistic effects of nateglinide (a non-sulfonylurea D-phenylalanine derivative) and meals on insulin secretion in 24 patients with type 2 diabetes. Oral doses of 60 and 180 mg or 120 and 240 mg were administered to two cohorts of subjects 10 min before meals (or fasting) three times daily for 7 days, with washout intervals between treatment periods. Dose-dependent increases in plasma insulin occurred, with the peak effect within 2 h after treatment. Significantly greater insulin secretion was observed when nateglinide was taken before a meal compared to nateglinide given in the fasted state or in response to just the meal. Nateglinide lowered plasma glucose concentrations significantly vs. placebo at all doses, and doses of 120 and 240 mg were more effective than 60 mg (P < 0.05). Adverse event rates were similar for nateglinide and placebo, and no hypoglycemic episodes or serious adverse events were reported during the study. Nateglinide (120 mg) was the maximum effective dose in this study and was shown to be a safe and well tolerated therapy for control of mealtime glucose excursions in patients with type 2 diabetes. Results indicate that a synergistic interaction occurs between nateglinide and elevated mealtime plasma glucose concentrations to stimulate insulin secretion.
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PMID:Synergistic effects of nateglinide and meal administration on insulin secretion in patients with type 2 diabetes mellitus. 1072 43

In this paper, the L-glutamate (L-Glu) transport system was targeted to improve the delivery of a model compound, p-di(hydroxyethyl)-amino-D-phenylalanine (D-MOD), through the blood-brain barrier (BBB) in vitro cell culture model. D-MOD is an analogue of an antitumor agent D-melphalan. To target the L-Glu transport system, D-MOD was conjugated to L-Glu to give D-MOD-L-Glu conjugate. D-MOD and D-MOD-L-Glu transport properties were evaluated using the bovine brain microvessel endothelial cell (BBMEC) monolayers. The results suggest that D-MOD-L-Glu conjugate permeates through the BBMEC monolayers more readily than the parent D-MOD. The improvement of transport may be due to the recognition of D-MOD-L-Glu by the L-Glu transport system. The transport mechanism was evaluated using several different experiments including: (a) concentration-dependent studies; (b) temperature-dependent studies; (c) substrate inhibition studies; and (d) metabolic inhibitor studies. The D-MOD-L-Glu transport was inhibited by the change of temperature from 37 degrees C to 4 degrees C. At higher concentrations, the transport of D-MOD-L-Glu reached plateau due to saturation. Furthermore, some amino acids (i.e., L-Glu, L-Asp, D-Asp, and L-Gln) inhibited the transport of D-MOD-L-Glu; presumably the conjugate was competing with these amino acids for the same transport system. Metabolic inhibitors (i.e., 2,4-dinitrophenol and sodium azide) suppressed the transport of the conjugate. However, the conjugate was not transported by monocarboxylic acid, dipeptide and neutral amino acid transporters. In conclusion, the L-Glu transport system can be utilized to facilitate a non-permeable drug across the BBB by conjugating the drug with L-Glu amino acid.
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PMID:Enhancement of transport of D-melphalan analogue by conjugation with L-glutamate across bovine brain microvessel endothelial cell monolayers. 1093 29

Nateglinide is a novel D-phenylalanine derivative that inhibits ATP-sensitive K+ channels in pancreatic beta-cells in the presence of glucose and thereby stimulates the prandial release of insulin. Nateglinide reduces fasting and mealtime blood glucose levels in animals, healthy volunteers, and patients with type 2 (non-insulin-dependent) diabetes mellitus, and produces prompt prandial insulin responses with return to baseline insulin levels between meals. In randomised, double-blind 24-week studies in patients with type 2 diabetes, oral nateglinide 120 mg 3 times daily before meals improved glycaemic control significantly relative to placebo. Nateglinide 120 mg plus metformin 500 mg, both 3 times daily, conferred greater glycaemic improvement than either drug given alone, and nateglinide 60 or 120 mg 3 times daily plus metformin 1 g twice daily was superior to metformin plus placebo. Nateglinide 120 mg 3 times daily significantly reduced hyperglycaemia relative to placebo in a 16-week double-blind study in patients with type 2 diabetes mellitus. Combination therapy with troglitazone 600 mg daily produced significantly better glycaemic control than either drug given as monotherapy. Mild hypoglycaemia was the most frequently reported adverse event (1.3% of patients) after treatment with nateglinide 120 mg 3 times daily in a 16-week clinical study. No clinically significant abnormalities in laboratory results, ECGs, vital signs or physical examination findings have been noted in patients taking the drug.
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PMID:Nateglinide. 1103 Apr 70

We investigated whether genetic variability in neurogenin-3, a basic helix-loop-helix transcription factor that is expressed in the developing pancreas, contributes to the etiology of maturity-onset diabetes of the young or other forms of autosomal dominant diabetes. Ninety-one probands of families with autosomal dominant diabetes were screened for neurogenin-3 mutations by dideoxy fingerprinting. Three sequence differences were identified: a polymorphism not affecting the amino acid sequence (L75L), a CA insertion/deletion in intron 1 (-44ins/del), and a C to T transition causing a serine to phenylalanine substitution (S199F). None of these sequence differences were more frequent in the family probands than in 179 nondiabetic controls. In contrast, allele 199F was weakly, but significantly, associated with common type 2 diabetes (199F frequencies = 0.436 in 132 cases with type 2 diabetes vs. 0.346 in the family probands and 0.346 in controls; P = 0.05). The relative risk of type 2 diabetes for 199F carriers was 1.7 (95% confidence interval, 1.04-2.7). We conclude that sequence differences in the neurogenin-3 gene do not play a major role in the development of autosomal dominant diabetes. Rather, they might contribute to common type 2 diabetes, although this finding must be replicated in other populations.
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PMID:Mutation screening of the neurogenin-3 gene in autosomal dominant diabetes. 1134 45

In vitro studies have shown that conjugation of a model compound [p-di(hydroxyethyl)-amino-D-phenylalanine (D-MOD)] with L-Glu can improve D-MOD permeation through the bovine brain microvessel endothelial cell monolayers (Sakaeda et al., 2000). The transport of this D-MOD-L-Glu conjugate is facilitated by the L-Glu transport system. In this paper, we evaluate the in vivo brain delivery of model compounds (i.e. D-MOD, p-nitro-D-phenylalanine (p-nitro-D-Phe), 5,7-dichlorokynurenic acid (DCKA) and D-kyotorphin) and their L-Glu conjugates. DCKA was also conjugated with L-Asp and L-Gln amino acids. The analgesic activities of D-kyotorphin and its L-Glu conjugate were also evaluated. The results showed that the brain-to-plasma concentration ratio of D-MOD-L-Glu was higher than the D-MOD alone; however, the plasma concentration of both compounds were the same. The plasma concentration of p-nitro-D-Phe-L-Glu conjugate was higher than the parent p-nitro-D-Phe; however, the brain-to-plasma concentration ratio of p-nitro-D-Phe was higher than its conjugate. On the other hand, both DCKA and DCKA conjugates have a low brain-to-plasma concentration ratio due to their inability to cross the blood-brain barrier (BBB). The L-Asp and L-Glu conjugates of DCKA have elevated plasma concentrations relative to DCKA; however, the DCKA-L-Gln conjugate has the same plasma concentration as DCKA. For D-kyotorphin, both the parent and the L-Glu conjugate showed similar analgesic activity. In conclusion, conjugation of a non-permeable drug with L-Glu may improve the drug's brain delivery; however, this improvement may depend on the physicochemical and receptor binding properties of the conjugate.
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PMID:Conjugation with L-Glutamate for in vivo brain drug delivery. 1137 21

Platelet levels of 19 amino acids were measured in 20 outpatients with type 1 (age [mean +/- SE], 35.5 +/- 2.0 years) and 27 with type 2 (age, 58.4 +/- 1.4 years) diabetes, and 20 young (age 33.7 +/- 1.3 years) and 20 older (age 57.4 +/- 1.5 years) healthy volunteers. Platelet levels of most amino acids tended to be lower in patients with type 1 diabetes than in healthy controls. In particular, asparagine, glycine, taurine, alanine, valine, cysteine, leucine, phenylalanine, and lysine levels, expressed as nmol/10(8) platelets, were significantly lower. Only taurine significantly decreased in patients with type 2 diabetes, whereas threonine, alanine, and isoleucine increased.
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PMID:Preliminary report: Amino acid profile in platelets of diabetic patients. 1143 75

It has been shown recently that troglitazone exerts an anti-inflammatory effect, in vitro, and in experimental animals. To test these properties in humans, we investigated the effect of troglitazone on the proinflammatory transcription factor nuclear factor-kappaB and its inhibitory protein IkappaB in mononuclear cells (MNC) and plasma soluble intracellular adhesion molecule-1, monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, and C-reactive protein. We also examined the effect of troglitazone on reactive oxygen species generation, p47(phox) subunit expression, 9-hydroxyoctadecadienoic acid (9-HODE), 13-HODE, o-tyrosine, and m-tyrosine in obese patients with type 2 diabetes. Seven obese patients with type 2 diabetes were treated with troglitazone (400 mg/day) for 4 weeks. Blood samples were obtained at weekly intervals. Nuclear factor-kappaB binding activity in MNC nuclear extracts was significantly inhibited after troglitazone treatment at week 1 and continued to be inhibited up to week 4. On the other hand, IkappaB protein levels increased significantly after troglitazone treatment at week 1, and this increase persisted throughout the study. Plasma monocyte chemoattractant protein-1 and soluble intracellular adhesion molecule-1 concentrations did not decrease significantly after troglitazone treatment, although there was a trend toward inhibition. Reactive oxygen species generation by polymorphonuclear cells and MNC, p47(phox) subunit protein quantities, plasminogen activator inhibitor-1, and C-reactive protein levels decreased significantly after troglitazone intake. 13-HODE/linoleic acid and 9-HODE/linoleic acid ratios also decreased after troglitazone intake. However, o-tyrosine/phenylalanine and m-tyrosine/phenylalanine ratios did not change significantly. These data show that troglitazone has profound antiinflammatory effects in addition to antioxidant effects in obese type 2 diabetics; these effects may be relevant to the recently described beneficial antiatherosclerotic effects of troglitazone at the vascular level.
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PMID:Nuclear factor-kappaB suppressive and inhibitor-kappaB stimulatory effects of troglitazone in obese patients with type 2 diabetes: evidence of an antiinflammatory action? 1144 97

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, interactions, and dosage of nateglinide are reviewed. Nateglinide is an oral hypoglycemic agent approved for use alone or in combination with metformin as an adjunct to diet and exercise for the treatment of type 2 diabetes mellitus. Nateglinide, an amino acid derivative of D-phenylalanine, stimulates the secretion of insulin by binding to the ATP potassium channels in pancreatic beta cells. The result is an increase in beta-cell calcium influx, which leads to rapid, short-lived insulin release. The drug is rapidly and completely absorbed in the small intestine. The estimated bioavailability is 72%. Nateglinide is highly bound to plasma proteins, is metabolized extensively by the liver, and has an elimination half-life of 1.4 hours. Several clinical trials of nateglinide, alone and in combination with other oral hypoglycemic agents, have found the drug to be safe, effective, and well tolerated. The most common adverse effects are nausea, diarrhea, dizziness, and lightheadedness. There is a potential for interactions between nateglinide and medications affected by the cytochrome P-450 isoenzyme system. Dosage regimens ranging from 60 to 240 mg have been evaluated. The maximum effective dosage is 120 mg taken 10 minutes before meals three times a day. Nateglinide is an alternative to second-generation sulfonylureas for the treatment of type 2 diabetes mellitus. Additional comparative trials are needed to fully elucidate nateglinide's role.
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PMID:Nateglinide. 1144 77

Current antidiabetic agents do not suppress insulin resistance, do not reinstate physiological insulin secretion and fail to prevent the gradual loss of B-cell function. Thus, these molecules are unable to maintain long term euglycemia in all type 2 diabetic patients and there is a need for new antidiabetic drugs. Thiazolidinediones (TZD) are a new class of insulin sensitizers recently approved in Europe, in combination therapy with sulfonylureas or/and metformin, for the treatment of type 2 diabetes. TZD show beneficial effects on insulin action, glucose homeostasis and lipid metabolism despite a substantial weight gain. Their potential protective effect on B-cell function and on the development of macrovascular complication is of particular interest. Non TZD PPARgamma agonists are also under clinical trials. Other interesting therapeutic perspectives to treat insulin resistance lie in the development of inhibitors of protein tyrosine phosphatases and in the promotion of non insulin-dependent contraction-like muscle glucose uptake via stimulation of AMP protein kinase (AMPK). As to new insulin secretagogues, the phenylalanine derivative nateglinide is a first phase insulin secretion enhancer primarily intended at controlling post-prandial hyperglycemia. The most promising perspective to improve B-cell function lies in the development of glucagon-like peptide-1 (GLP-1) analogs. Clinical studies show beneficial effects on glucose homeostasis in type 2 diabetics and efficacy in sulfonylurea resistant patients without risk of hypoglycaemia. Animal studies predict beneficial effects on B-cell mass. Finally we will discuss the potential use of gene therapy to treat insulin resistance and B-cell dysfunction.
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PMID:Therapeutic perspectives for type 2 diabetes mellitus: molecular and clinical insights. 1154 15

Although a traditional goal of glycemic control in the treatment of diabetes mellitus is to normalize fasting plasma glucose, emerging data indicate that modulation of postprandial plasma glucose levels plays an important role in overall glycemic control. This article reviews the evidence linking postprandial glucose levels with long-term indices of diabetes control, such as glycosylated hemoglobin, lipid abnormalities, and the risk of microvascular and macrovascular complications. Early in the development of type 2 diabetes, the initial burst of insulin release in response to food intake is compromised, allowing postprandial hyperglycemia to develop. Meal-associated hyperglycemia further contributes to increase insulin resistance and decrease insulin production. Evidence of a strong correlation between high postprandial glycemic levels and the development of vascular complications underscores the significance of treating mealtime glycemia. Emerging drugs that reduce postprandial hyperglycemia include the D-phenylalanine derivative nateglinide, amylin derivative pramlintide, and glucagon-like insulinotropic peptide.
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PMID:Importance of postprandial glucose control. 1154 92


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