• The Korean Journal of Physiology
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• v.21 no.2
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• pp.283-289
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• 1987

Uric acid transport across the basolateral membrane of renal proximal tubules was studied in rabbit kidney cortical slices. Uric acid uptake was greater under $O_2$ atmosphere compared to under $N_2$ atmosphere, and was increased with $Na^{2+}$ concentration in incubation medium. Uric acid inhibited PAH uptake but not TEA uptake and did trans-stimulated PAH efflux. PAH also inhibited uric acid uptake. Uric acid uptake was inhibited by harmaline, ouabin, SITS, DIDS and pyrazinoic acid. The inhibition of PAH uptake by these inhibitors also was reasonably comparable to that of uric acid uptake. These results suggest that uric acid was transported across the basolateral membrane of renal tubule by a carrier-mediated process which was by a common transport system with PAH in rabbit.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.595-604
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• 2016

It has been reported that the increased uric acid level is associated with metabolic syndrome risk factors in both male and female. However, there has not been enough studies to investigate gender differences of this association in Korea. To evaluate relation between serum uric acids and metabolic syndrome markers, anthropometric and biochemical analyses data was obtained from National Health Examination 2005 and 5,523 (M=3,097; F=2,426) data was analyzed. Results by quartile of serum uric acid levels in females showed that increased serum uric acid level was associated with elevated levels of total-. LDL-cholesterol, and triglycerides, whereas association between serum uric acid and total cholesterol levels was not observed in male subjects. In both female and male, higher quartile of serum uric acid level were linked with lower levels of HDL-cholesterol. In regression analysis, association of serum uric acid levels with fasting glucose levels was significant in female subjects only. In conclusion, higher serum uric acid levels were associated with metabolic syndrome indices, however gender differences were existed for total cholesterol.

• Biomolecules & Therapeutics
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• v.31 no.1
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• pp.89-96
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• 2023

Uric acid produced by guanine deaminase (GDA) is involved in photoaging and hyperpigmentation. Reactive oxygen species (ROS) generated by uric acid plays a role in photoaging. However, the mechanism by which uric acid stimulates melanogenesis in GDA-overexpressing keratinocytes is unclear. Keratinocyte-derived paracrine factors have been identified as important mechanisms of ultraviolet-induced melanogenesis. Therefore, the role of paracrine melanogenic growth factors in GDA-induced hypermelanosis mediated by uric acid was examined. The relationships between ROS and these growth factors were examined. Primary cultured normal keratinocytes overexpressed with wild type or mutant GDA and those treated with xanthine or uric acid in the presence or absence of allopurinol, H₂O₂, or N-acetylcysteine (NAC) were used in this study. Intracellular and extracellular bFGF and SCF levels were increased in keratinocytes by wild type, but not by loss-of-function mutants of GDA overexpression. Culture supernatants from GDA-overexpressing keratinocytes stimulated melanogenesis, which was restored by anti-bFGF and anti-SCF antibodies. Allopurinol treatment reduced the expression levels of bFGF and SCF in both GDA-overexpressing and normal keratinocytes exposed to exogenous xanthine; the exogenous uric acid increased their expression levels. H₂O₂-stimulated tyrosinase expression and melanogenesis were restored by NAC pretreatment. However, H₂O₂ or NAC did not upregulate or downregulate bFGF or SCF, respectively. Overall, uric acid could be involved in melanogenesis induced by GDA overexpression in keratinocytes via bFGF and SCF upregulation not via ROS generation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.627-634
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• 2016

The aim of this study was to examine the impact of the obesity status on serum uric acid in health check-up examinees. The study subjects were 1,118 adults, 20 years and over (636 males, 482 females), the health package check-up at the general hospital in Gwang-Ju from January to December, 2011. This study assessed the serum uric acid, blood urea nitrogen, and creatinine levels, as well as the anthropometric variables (SBP, DBP, and BMI). In a model I, after adjusting for the variables, such as age, SBP, DBP, TC, TG, HDL-C, and FBG, the mean uric acid level ($M{\pm}SE$) increased with increasing obesity status in males (p<0.001) or females (p=0.036). In model II, after adjusting for BUN and creatinine, the mean uric acid ($M{\pm}SE$) in males increased with increasing obesity status (Normal weight [BMI <$23.0kg/m^2$], $4.89{\pm}0.07mg/dl$; overweight [BMI $23.0-24.9kg/m^2$], $5.01{\pm}0.09mg/dl$; obesity [BMI ${\geq}25.0kg/m^2$], $5.35{\pm}0.08mg/dl$) (p<0.001). In the females, however, the mean uric acid ($M{\pm}SE$) did not increase with increasing obesity status (Normal weight, $5.03{\pm}0.08mg/dl$; overweight, $5.19{\pm}0.11mg/dl$; obesity, $5.27{\pm}0.09mg/dl$) (p=0.191). In conclusion, these results suggest that an increase in obesity status is associated with an increase in the serum uric acid levels in males, but not in females.

• Biomedical Science Letters
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• v.17 no.2
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• pp.113-122
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• 2011

Several studies have reported a relation between serum levels of uric acid and a wide variety of cardiovascular conditions. But, the relationship between serum levels of uric acid and coronary artery disease (CAD) is still controversial. The present study was retrospectively designed to investigate whether CAD can be stratified by the level of uric acid and there are the relationships between preoperative levels of uric acid and perioperative biochemical markers in fifty-adult patients that underwent coronary artery bypass grafting surgery (CABG) and twenty-normal subjects. They were divided into the control, the unstable angina (UA-group) and the myocardial infarction group (MI-group). In preoperative levels of uric acid, the MI-group was higher than control and the UA-group. The MI-group had significantly higher correlations than the UA-group between preoperative levels of uric acid and left ventricular ejection fraction, cardiac markers (creatine kinase, lactate dehydrogenase and brain natriuretic peptide), renal markers (blood urea nitrogen and creatinine) or total leukocyte levels. At postoperative periods, the MI-group had higher relationships of uric acid with aspartate aminotransferase, blood urea nitrogen or creatinine levels. Although there was not statistically significant, the UA-group tended to have higher correlation coefficients than the MI-group between preoperative levels of uric acid and intensive care unit-stay (ICU), or postoperative mechanical ventilation time. These results reflect that increased levels of serum uric acid may be a tool for the diagnosis of coronary heart disease and may be considered as a good predictor in assessing the cardiac and renal functions in patients with myocardial infarction or unstable angina at the preoperative period. However, further studies should be performed in a large patient population.

• Journal of the Korean Dietetic Association
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• v.28 no.3
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• pp.169-181
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• 2022

This study evaluated the correlation between serum uric acid level and the nutrients adequacy ratio (NAR) using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016~2019. This is a cross-sectional study in which 6,579 Korean male adults were divided into quartiles according to their uric acid levels. All analyses were performed with adjusted age. Uric acid decreased as the age increased from the age group 19~29 years to 30~49 years and then to 50~64 years. Interquartile results of serum uric acid levels showed that increases in the serum uric acid levels were associated with decreases in LDL-cholesterol (P<0.01), triglycerides (P<0.001), body weight (P<0.001), waist circumference (P<0.001), body mass index (P<0.001), systolic blood pressure (SBP) (P<0.001), diastolic blood pressure (DBP) (P<0.001). However, uric acid levels decreased with an increase in HDL cholesterol (P<0.001). The analysis of the NARs according to the quartiles of serum uric acid levels in men showed that an increase in serum uric acid levels was associated with a decrease in the NAR levels of dietary fiber (P<0.001), calcium (P<0.001), and folic acid (P<0.001).

• Biomedical Science Letters
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• v.23 no.2
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• pp.118-127
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• 2017

Elevated serum uric acid and resting heart rate are risk factors and predictors of metabolic syndrome. However, few studies have examined the optimal cutoff value for serum uric acid and resting heart rate to predict metabolic syndrome in Korean adults. Subjects for this study were 22,302 adults (average age 45 years old), who underwent health screening examination from January 2010 to December 2012 at the Health Promotion Center of one hospital in Gyeonggi-do for general health check-up. The uric acid and resting heart rate cutoff values were calculated by ROC analysis for metabolic syndrome. Elevated serum uric acid and resting heart rate were associated with an increased prevalence of metabolic syndrome in Korean adults. The optimal cutoff value for uric acid level to predict metabolic syndrome in adults was 4.95 mg/dL (male 6.35, female 4.55) and optimal cutoff value for resting heart rate to predict metabolic syndrome was 68 beats per minute (male 66, female 68). However, serum uric acid and resting heart rate were found to have limitations for the diagnosis of metabolic syndrome.

• Journal of Preventive Medicine and Public Health
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• v.45 no.3
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• pp.181-187
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• 2012

Objectives: Serum uric acid levels have been reported to be associated with a variety of cardiovascular conditions. However, the direct association between uric acid levels and metabolic syndrome remains controversial. Thus, we evaluated the association of serum uric acid levels and metabolic syndrome in a community-based cohort study in Korea. Methods: We performed cross-sectional analysis of baseline data of 889 males and 1491 females (aged 38 to 87) who participated in baseline examinations of the Korean Genome and Epidemiology Study: Kanghwa study. Blood samples were collected after at least an 8 hour fast. Uric acid quartiles were defined as follows: <4.8, 4.8-<5.6, 5.6-<6.5, ${\geq}6.5$ mg/dL in males; and <3.8, 3.8- <4.3, 4.3 - <5.1, ${\geq}5.1$ mg/dL in females. Metabolic syndrome was defined by the National Cholesterol Education Program Adult Treatment Panel III Criteria with adjusted waist circumference cutoffs (90 cm for males; 80 cm for females). The association between serum uric acid quartiles and metabolic syndrome was assessed using multivariate logistic regression. Results: The odds ratio for having metabolic syndrome in the highest versus lowest quartiles of serum uric acid levels was 2.67 (95% confidence interval [CI], 1.60 to 4.46) in males and 2.14 (95% CI, 1.50 to 3.05) in females after adjusting for age, smoking, alcohol intake, body mass index, total cholesterol, HbA1c, albumin, ${\gamma}$-glutamyltransferase, blood urea nitrogen, and log C-reactive protein. The number of metabolic abnormalities also increased gradually with increasing serum uric acid levels (adjusted p for trend < 0.001 in both sexes). Conclusions: Higher serum uric acid levels are positively associated with the presence of metabolic syndrome in Korean males and females.

• Journal of Preventive Medicine and Public Health
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• v.35 no.3
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• pp.214-220
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• 2002

Objectives : To investigate the relationship of serum uric acid to cardiovascular risk factors in Korean male workers. Methods : We screened 522 male workers at an electrical manufacturing company by a periodic health examination and a questionnaire survey in 2000. We collected data relating to age, smoking status, alcohol drinking status, body mass index (BMI), blood pressure, serum lipid, fasting blood glucose and serum uric acid. The data were analyzed using a variety of methods, including ANOVA, Pearson's correlation, and multivariate regression analyses. to examine the association between uric acid and cardiovascular risk factors with a cross-sectional study design. Results : The concentration of serum uric acid showed positive associations with BMI, total cholesterol, triglyceride, and LDL-cholesterol; it was also significantly correlated to systolic and diastolic blood pressures. Life-style characteristics, such as smoking and alcohol drinking showed no significant association. From the multivariate regression analyses, BMI, total cholesterol and fasting blood glucose levels were found to be independent positive predictors of uric acid; while age, blood pressure and smoking status give no independent contribution explaining the variability of serum uric acid levels. Conclusions : This study demonstrates that serum uric acid level have a significant association with cardiovascular risk factors, such as BMI, total cholesterol and blood glucose in some Korean male workers.

• Childhood Kidney Diseases
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• v.25 no.2
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• pp.78-83
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• 2021

Background: Uric acid levels in urine are measured using urine specimens 24 hours or by uric acid glomerular filtration rate (UAGFR) with spot urine, which additionally requires a blood sample. This study aimed to investigate whether urinary uric acid creatinine ratio (UUACr) obtained by spot urine alone could be recognized as a substitute for UAGFR value, and hyperuricosuria can be screened by UUACr. UUACr is known to vary with age and regional differences. This study focused on the reference value of each value in Korean young populations. Method: We enrolled Korean subjects 1-20 years with normal kidney function, from a single hospital, classified into 5 age groups, 1-5 years, 6-8 years, 9-12 years, 13-15 years, and 16-20 years. We checked spot urine uric acid, creatinine and serum uric acid, creatinine levels on the same day from February 2014 to December 2018. We measured the average of UAGFR and UUACr in each groups. The UUACr cut-off value of the upper 2 standard deviation (SD) of UAGFR were taken. Results: The upper 2 SD of UUACr (mg/mg) and UAGFR (mg/dL) were determined in all age groups. UUACr decreased with grown up (P=0.000), but UAGFR were not statistically different among the groups. UUACr and UAGFR were not significantly different by gender. UUACr and UAGFR were positively correlated; UUACr cut-off value of upper 2 SD UAGFR (0.54 mg/dL) was 0.65 mg/mg in total age. Conclusions: UUACr could potentially be used to screen for hyperuricosuria.