• The Korean Journal of Pharmacology
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• v.7 no.1
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• pp.67-76
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• 1971

The excretion of uric acid in man has been of great interest because of its importance as an end product in purine metabolism as well as of its role in causing gout. There are many differences in the modes of renal handling of urate among various species of animals. Uric acid actively secreted by the renal tubules of most vertebrate including amphibians, reptiles, and birds. On the other hand, in most mammals net tubular reabsorption of urate appears to be occurred with some exception, such, as Dalmatian dog. In the rabbits, however, the mechanism of renal excretion of uric acid has long been a subject of controversial results. Within a given group it was possible to find individuals with either net secretion or net reabsorption of urate depend on the experimental conditions. Excretion of urate can be depressed or enhanced by a variety of drugs belonging mainly to the aromatic acid group. Diodrast, probenecid, cinchophen and salicylates have been reported as uricosuric agents, on the other hand, lactate, benzoate, pyrazinoic acid, acetazolamide and chlorothiazide are known to be contraindicated to use for the patient with gout since these agents depress the excretion of uric acid from the kidney. However, complex and sometimes the paradoxical effects on the urate excretion by those above mentioned drugs are not uncommon. The experiments were designed to investigate the mechanisms of renal handling of urate as well as the effects of variety of drugs on the tubular transport of uric acid in the rabbits. Male or female white rabbits, from 1.5 to 2.5 kg in weight, were used. The experimental methods used in these studies were clearance, stop-flow, and retrograde injection techniques. The effects of saline, salicylate, chlorothiazide and probenecid were investigated in each experimental conditions. Results of the experiments were summarized as follows; 1. In the rabbits, the rate of urate clearance was always lower than the rate of inulin clearance. The filtration fraction of the urate was one third on an average, therefore, it is estimated that approximately two thirds of filtered urate was reabsorbed. 2. In the kidneys of rabbits, the urate clearance was increased significantly by administration of chlorothiazide and decreased by probenecid. The administration of salicylate had no effect on the rate of urate clearance. The filtration fraction of urate was increased by chlorothiazide and decreased by probenecid. 3. In the stop-flow studies, the U/P ratio of urate was higher than the U/P ratio of inulin in the proximal region, indicating the secretion of uric acid in the proximal tubules. The proximal peak was increased by chlorothiazide and inhibited by probenecid.4. In the retrograde injection studies, the reabsorption of urate in the proximal region was observed, and these reabsorptive transport of urate was depressed by either probenecid or by chlorothiazide. 5. No distal tubular activity was observed under any of these experimental conditions concerning urate transport. The results of these experiments show that probenecid inhibits both secretory and reabsorptive transport of uric acid in the kidney of the rabbits. The enhancement of secretory transport of urate by chlorothiazide in the clearance study was due to the secondary action of chlorothiazide which inhibits the reabsorptive transport of urate in the proximal tubules. It is evident that the urate transport in the kidneys of rabbits is bidirectional nondiffusive flux both secretory and reabsorptive directions in the proximal tubules.

• Translational and Clinical Pharmacology
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• v.25 no.2
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• pp.67-73
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• 2017

Glimepiride, a third generation sulfonylurea, is an antihyperglycemic agent widely used to treat type 2 diabetes mellitus. In this study, an untargeted urinary metabolomic analysis was performed to identify endogenous metabolites affected by glimepiride administration. Urine samples of twelve healthy male volunteers were collected before and after administration of 2 mg glimepiride. These samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and then subjected to multivariate data analysis including principal component analysis and orthogonal partial least squares discriminant analysis. Through this metabolomic profiling, we identified several endogenous metabolites such as adenosine 3', 5'-cyclic monophosphate (cAMP), quercetin, tyramine, and urocanic acid, which exhibit significant metabolomic changes between pre- and posturine samples. Among these, cAMP, which is known to be related to insulin secretion, was the most significantly altered metabolite following glimepiride administration. In addition, the pathway analysis showed that purine, tyrosine, and histidine metabolism was affected by pharmacological responses to glimepiride. Together, the results suggest that the pharmacometabolomic approach, based on LC-MS/MS, is useful in understanding the alterations in biochemical pathways associated with glimepiride action.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.14 no.2
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• pp.97-101
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• 2018

Lesch-Nyhan syndrome is a rare X-linked recessive genetic disorder. During purine metabolism, the hypoxanthine guanine phosphribosyl transferase (HGPRT) enzyme is deficient causing phosphoribosyl transferase to accumulate and resulting in excessive uric acid. Clinical symptoms include hypercalcemia, choreoathetosis, spasticity, mental retardation, and self-injury to lips, tongue or fingers. This results not only in pain caused by the self-injury but also secondary infection of the wound site and the esthetic damage of the soft tissue defect. Dental treatments include conservative methods using intraoral appliances such as soft mouthguards, fixed lip bumpers, and occlusal guards, and invasive methods such as extraction of all teeth or forming an artificial anterior open bite. We report two cases of Lesch-Nyhan syndrome patients with self-mutilation behavior; one was treated with a preservative method using a soft mouthguard, and the other was treated with extraction of all teeth.

• Journal of Life Science
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• v.29 no.1
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• pp.37-44
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• 2019

Leaves of Sasa quelpaertensis Nakai are used in folk medicine for their anti-inflammatory, antipyretic, and diuretic properties. To ensure efficient utilization of S. quelpaertensis leaf, we previously reported a preparation method for phytochemical-rich extract (PRE) using the leaf residue, which was produced after hot water extraction. This study was undertaken to evaluate the hypouricemic potential of S. quelpaertensis leaf PRE in potassium oxonate (PO)-induced hyperuricemic mice. The administration of PRE significantly reduced serum uric acid (UA), blood urea nitrogen (BUN), and serum creatinine levels and increased urine UA and creatinine levels in the PO-induced hyperuricemic mice. It also reduced liver UA levels and xanthine oxidase (XA) activity. A histological analysis revealed that PRE administration protected against PO-induced liver damage, pointing to anti-inflammatory and cytoprotective effects in PO-induced hyperuricemic mice. We analyzed the transcriptome response to PRE administration in PO-induced hyperuricemic mice using RNA sequencing (RNA-Seq) in kidney tissues. The administration of PRE mainly enriched genes involved in mediating immune and inflammatory responses and the metabolic pathway. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the metabolic pathway, purine metabolism, and antibody biosynthesis were the major pathways altered in the PRE and PO groups. These results suggest a potential role for PRE in the prevention and treatment of hyperuricemia with inflammation.

• Childhood Kidney Diseases
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• v.2 no.1
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• pp.41-49
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• 1998

Treatment of $Henoch-Sch\"{o}nlein$ purpura nephritis(HSPN) accomanied by nephrotic syndrome is still controversal, even though both corticosteroids and immunosuppressants have been used for therapy. Azathioprine(AZA) is a chemical analog of the physiologic purines-adenine, guanine, and hyoxanthine and an antagonist to purine metabolism which may inhibit RNA and DNA synthesis and is mainly used for immunosuppressive agent. We studied the effects of AZA in HSPN accompanied by nephrotic syndrome and evaluating the clinical status and histopathologic changes by sequential biopsies following the treatment. Fifteen patients with nehprotic syndrome either initially or during the course of HSPN confirmed by renal biopsies were treated with AZA(2 mg/kg/day) and prednisolone (0.5-1 mg/kg/day qod) for 8months. Folow up renal biopsy was done after treatment in 11 patients. The clinical status of the patients on admission were C(12 cases) and B(3 cases). Improvement of clinical status were showed in 12 cases, but 3 cases were not improved and 1 case was aggrevated after AZA treatment. Complete remission of proteinuria were in 8 cases(53.3%), partial remission were in 4 cases(26.7%) and persistence of proteinuria and hematuria were in 3 cases(20.0%). The loss of hematuria were in 10 cases(66.7%). Histopathologically and immunopathologically, 4 cases were improved. This study suggests that, although control studies are needed, AZA could be used in the treatment of HSPN accompanied by nephrotic syndrome.