Effects of profuse sweating induced by exercise on urinary uric acid excretion in a hot environment

In order to determine whether exercise-induced profuse sweating could reduce urinary uric acid excretion, we simulated badminton players training and measured their uric acid in urine, sweat and blood during the training period. Thirteen male volunteers who were well-trained badminton players were recruited in this study. On the first 2 days and the last 2 days of the study period none of the subjects engaged in any intense exercise- or activity-inducing profuse sweat, but they accepted routine training 2 h per day during the middle 3 days. The results show that mean serum urate levels of thirteen volunteers rose significantly on day 4, when the concentrations increased by 18.2% over day 2 (P < 0.05). The mean ten-hour urinary uric acid excretion of seven volunteers on the 3 training days was significantly less at 178.5 micromol/day and 118.3 micromol/day than those on the preceding and subsequent days of the training days, respectively (P < 0.05). Furthermore, for six volunteers, the mean ratio of clearance of uric acid to creatinine was 6.6% on day 2, which significantly decreased to 5.4% on day 4 (P < 0.05). It is concluded profuse sweating exercise results in a decrease of urinary uric acid excretion amounts and leads to increased serum uric acid after the exercise. We suggest that persons who take vigorous exercise or are exposed to hot environments need drinking enough fluids to prevent dehydration and maintain adequate urinary output. People with profuse sweat after rigorous exercise are recommended taking sports drinks containing abundant sodium in order to decrease serum uric acid.     

Biochemical variables in plasma and urine before and after prolonged physical exercise

Nine normal young male students were studied during 2 days of relative rest, during 2 days of physical training and again during the succeeding 2 days of relative rest. 24-hour urine collections showed that the creatinine, creatine, uric acid, urea, calcium and magnesium excretion were similar during the resting and exercise days. The 24-hour urinary excretion of sodium and potassium was decreased during the exercise days, while the aldosterone excretion was increased. The hemoglobin concentration, hematocrit and red cell counts were decreased 14, as well as 42 h after exercise. The serum uric acid, creatine phosphokinase-MM (skeletal muscles) subfraction, glutamic oxalacetic transaminase and myoglobin levels were increased 14 h after exercise, but returned to baseline 42 h after this type of exercise. The mechanisms of these alterations were discussed and the data show that one should take into account previous exercise when interpreting the results of certain of these tests.     

几种天然产物对高尿酸血症大鼠血清尿酸水平的影响初探

目的:探讨几种天然产物对高尿酸血症大鼠血清尿酸水平及尿酸排泄的影响.方法:对wistar大鼠灌胃氧嗪酸钾和酵母膏,制作高尿酸血症大鼠动物模型.灌胃给药褐藻糖胶、柠檬酸钾和东哥阿里提取物,2周后采血并进行代谢实验,检测血清尿酸、尿素氮,24小时尿液体积、pH值、尿酸浓度及总量,分析三种活性物质对机体尿酸水平、尿酸排泄、肾脏功能的影响.结果:三种物质均可显著降低高尿酸血症模型大鼠的血清尿酸水平,其中东哥阿里提取物组的24小时排泄尿酸总量较模型组显著降低,褐藻糖胶对实验大鼠的血清尿素氮水平升高有抑制作用.结论:三种活性物质对高尿酸血症大鼠血清尿酸浓度有降低作用,其中褐藻糖胶对肾脏功能有保护作用,从而保证尿酸的顺利排泄,而东哥阿里在降低血尿酸水平的同时,24小时尿液中排泄的尿酸总量也显著低于模型对照组,其机制可能与抑制尿酸生成有关.     

Changes in zinc metabolism following exercise in human subjects

Changes in zinc (Zn) availability in muscle tissue that influence muscle performance in vitro have been observed. The effect of exercise of plasma Zn levels and urinary excretion of Zn was observed in sever untrained volunteers following brief intensive exercise and in seven trained volunteers after more prolonged road-running exercise. With brief exercise, plasma Zn decreased predominantly in the more loosely bound albumin fraction. Prolonged exercise resulted in a greater plasma Zn decrease of 30%. Urinary Zn excretion increased transiently with minimal effect on daily losses. However, weight loss by sweating was significant, and sweat Zn losses were greater than those in the urine. Exercise resulted in changes in Zn metabolism that may influence performance.     

Excretion of nitrogen compounds in sweat during a sauna]

The aim of the study was to determine a loss of nitrogen compounds with sweat in sauna and to estimate their plasma concentration. Sweat was collided during 30 min stay in sauna. Blood was taken before and immediately after the sauna. Concentrations of ammonia, urea, creatinine and uric acid were determined in the both fluids. It has been found, that the concentration of ammonia in sweat exceeds, that in plasma by 77 times. Ammonia plasma concentration following sauna increased by about 60%. Sweat urea concentration exceeded that in plasma by 3.5 times. Plasma urea concentration was significantly reduced after sauna. Sweat creatinine concentration was about two times higher than that in plasma. No uric acid was detected in sweat. Sweating did not affect plasma creatinine and uric acid concentrations. Results indicate that considerable amount of nitrogen is lost with sweat during sauna.     

Studies on Dysmetabolic Uratemia-Associated Nephropathy in Children of the Turkmenistan Arid Region

Dysmetabolic uratemia-associated nephropathy was studied in virtually healthy children of the preschool and early school age (27 patients) in Turkmenistan in autumn and in winter. All of the children had uricemia and/or uricosuria of various levels (moderately increased and the highest level). The decreased diuresis and glomerular filtration, nicturia or monotonic urine excretion, the increased relative urine density, the urinary syndrome, the data of ultrasonic examination, uricemia uricosuria suggest (of different level) a diagnosis of dysmetabolic, or urate, nephropathy. The urate nephropathy is specified by a decrease in the creatinine and urea excretion along with an increased excretion of uric acid. The elevated or high level to be caused by a metabolic disorder in purine metabolism and seems to be determined by a hereditary hyperproduction of uric acid due to deficiency of the hypoxanthine guanine phosphorybosyl transferase enzyme.     

Iodine uptake and loss-can frequent strenuous exercise induce iodine deficiency?

Most of the daily dietary iodine intake (approximately 90 %) will be excreted in the urine; measurement of urinary iodine excretion is thus routinely used as an index of dietary iodine intake. However, urinary excretion is not the only means of iodine loss. Subjects such as athletes or those participating in vigorous exercise can lose a considerable amount of iodine in sweat, depending on environmental factors such as temperature and humidity. In areas of lower to moderate dietary iodine intake, loss in sweat can equal that in urine. Although electrolyte loss in sweat is well-recognized and replacement strategies are adopted, there is less recognition of potential iodine loss. Crude calculations reveal that if sweat iodide losses are not replaced, dietary stores could be depleted in an athlete undergoing a regular training regime. The significance of these losses could be increased in areas where dietary iodine intake is lower in the summer months. Although there is little doubt that excessive sweating can induce a relative iodine deficiency state, there is no case as yet for iodine supplementation in those that take vigorous exercise. However, sustained iodine loss may have implications for thyroid status and possibly consequences for athletic performance.     

高龄老年男性高血压患者腔隙性脑梗死与血清尿酸水平的相关性研究

目的：探讨男性高龄高血压患者腔隙性脑梗死（LI）与血清尿酸水平的相关性。方法：以98例男性高龄高血压患者为对象,均行颅脑磁共振成像（MRI）检查和血清尿酸水平测定,同时收集患者的临床和其他实验室数据。根据患者尿酸水平分为1、2、3三组（n=32、32、34）。结果：以尿酸水平分组的患者一般资料比较,单因素方差分析提示,随着尿酸水平的增高,三组的LI个数、血肌酐、尿素水平增高,而高密度脂蛋白（HDL）水平降低,差异有统计学意义（P〈0.05）。三组患者的24 h收缩压、舒张压、年龄、总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL）和空腹血糖比较,差异无统计学意义（P〉0.05）;LI个数与影响因素的Spearman相关分析提示尿酸及尿素水平与腔梗个数相关（P〈0.05）;LI个数与影响因素的多元线性回归分析提示血清尿酸水平是影响LI个数的独立危险因素（P〈0.01）。结论：在高龄高血压患者中,尿酸水平的增高可能是LI的危险因素之一。     

Effect of vitamin E therapy on serum uric acid in DOCA-salt-treated rats

Uric acid is considered as an antioxidant in the blood. Despite its proposed protective properties, elevated plasma uric acid has been associated with hypertension in a variety of disorders. The purpose of this study was to investigate the relationship between the increase of arterial blood pressure and the changes in serum uric acid, measured during the gradual development of experimental hypertension in deoxycorticosterone (DOCA)-salt-treated rats. Blood pressure was monitored by tail-cuff method, urinary and plasma uric acid was measured by autoanalyzer during the induction of hypertension in 1-, 2-, 3- and 4-week DOCA-salt-treated Sprague-Dawley rats. Vitamin E (200 mg/kg/day/gavage) was co-administered with DOCA-salt for 4 weeks. From the first week of DOCA-salt treatment, rats exhibited marked increases in blood pressure. DOCA-salt treatment also resulted in a significant increase in serum uric acid and a significant decrease in urinary uric acid at the end of the first week. These changes in serum and urinary uric acid remained until the 4th week of DOCA-salt treatment but blood pressure continued to increase throughout the study. Vitamin E treatment increased urinary excretion of uric acid and decreased blood pressure and serum uric acid in DOCA-salt-treated rats. These data suggest that enhanced serum uric acid may be a contributing factor to the onset of hypertension in DOCA-salt-treated rats. A uricosuric effect is suggested for vitamin E in the treatment of hypertension.     

L-阿拉伯糖对尿酸的调节作用

转录因子是一类在生物生命活动过程中起到调控作用的重要因子,参与了各种信号转导和调控过程,可以直接或间接结合在顺式作用元件上,实现调控目标基因转录效率的抑制或增强,从而使植物在应对逆境胁迫下做出反应。 WRKY转录因子在大多数植物体内都有分布,是一类进化非常保守的转录因子家族,参与植物生长发育以及响应逆境胁迫的生理过程。众多研究表明,WRKY转录因子在植物中能够应答各种生物胁迫,如细菌、病毒和真菌等;多种非生物胁迫,包括高温、冷害、高光和高盐等;以及在各种植物激素,包括茉莉酸( JA)、水杨酸( SA)、脱落酸( ABA)和赤霉素( GA)等,在其信号传递途径中都起着重要作用。 WRKY转录因子家族蛋白至少含有一段60个氨基酸左右的高度保守序列,被称为WRKY结构域,其中WRKYGQK多肽序列是最为保守的,因此而得名。该转录因子的WRKY结构域能与目标基因启动子中的顺式作用元件W￣box( TTGAC序列)特异结合,从而调节目标基因的表达,其调控基因表达主要受病原菌、虫咬、机械损伤、外界胁迫压力和信号分子的诱导。该文介绍了植物WRKY转录因子在植物应对冷害、干旱、高盐等非生物胁迫与病菌、虫害等生物胁迫反应中的重要调控功能,并总结了WRKY转录因子在调控这些逆境胁迫反应过程中的主要生理机制。     

Urea excretion in sweat during short-term efforts of high intensity

The sweat urea excretion during different types of short-term efforts of high intensity was examined in well trained competitors. It has been found that considerable amounts of urea were excreted in the sweat during each exercise test investigated. It is concluded that the purine nucleotide cycle was the source of ammonia for the increased urea formation during the efforts.     

The Effects of Probenecid and Thiazides and Their Combination on the Urinary Excretion of Electrolytes and on Acid-base Equilibrium

The effects of commonly used therapeutic doses of hydrochlorothiazide and probenecid, given singly and in combination, on the urinary excretion of monovalent and divalent ions and on acid-base equilibrium were studied in four patients with idiopathic hypercalciuria.Probenecid had no effect on the urinary excretion of monovalent ions but resulted in a sustained increase in the urinary excretion of calcium, magnesium and citrate and a temporary increase in the urinary excretion of ammonium, in addition to its well-known effects on uric acid metabolism. A temporary fall in serum phosphorus levels was also observed.Probenecid also modified the response to hydrochlorothiazide in that the urinary excretion of calcium, magnesium and citrate was greater during combined therapy than when hydrochlorothiazide was administered alone. Probenecid prevented or abolished the increase in serum uric acid levels associated with the use of thiazide but did not modify the effects of hydrochlorothiazide on the urinary excretion of sodium, chloride, potassiu, phosphorus, ammonium, titratable acid and bicarbonate.     

Effect of purine-free low-malt liquor (happo-shu) on the plasma concentrations and urinary excretion of purine bases and uridine--comparison between purine-free and regular happo-shu.

To determine whether purine-free and regular low-malt liquor beverages (happo-shu) increase the plasma concentration and urinary excretion of purine bases (hypoxanthine, xanthine, uric acid) and uridine, 6 healthy males were given regular (10 ml/kg of body weight) and purine-free happo-shu (10 ml/kg of body weight). Plasma concentration-time curves were plotted, and the areas under the curves for uric acid and total purine bases (the sum of hypoxanthine, xanthine, and uric acid) were greater in the regular than in the purine-free happo-shu ingestion experiment (both p < 0.05). In addition, the total urinary excretion of xanthine, total purine bases, and uridine was greater in the regular than in the purine-free happo-shu ingestion experiment (p < 0.05 in all cases), although the total urinary excretion of hypoxanthine and uric acid was no different between the regular and the purine-free happo-shu ingestion experiments. These results suggest that uridine contained in regular happo-shu might contribute to an increase in the urinary excretion of uridine along with ethanol, and that the purines contained in regular happo-shu may contribute to the increase in plasma concentration of uric acid due to purine degradation.     

Effects of ornithine or arginine administration on serum amino acid levels

In healthy humans after overnight fasting, an oral administration of ornithine induced a new steady state: an accumulation of serum alanine and proline, a decrease in serum valine concentration, transient reductions in serum urea and urinary urea contents, and then an increased urea excretion. On the other hand, an oral administration of arginine resulted in an anabolic state: decreases in serum leucine and isoleucine concentrations, reductions in serum glucose and free fatty acid contents and a rapid increase in serum insulin level. It was assumed that the effect of ornithine administration may be exerted through an activation of hepatic System A transport and that of arginine is an insulin-mediated action.     

Untersuchungen zum Harnsäuremetabolismus vonLittorina littorea (Gastropoda)

Periwinkles, as typical inhabitants of sea-shores, are subjected to extreme changes of environmental conditions, which affect their excretion. InLittorina littorea uric acid, urea and ammonium were detected particularly in the kidney, but the only metabolite excreted was ammonium. Only the concentration of uric acid was dependent on the availability of water; decreasing periods of submersion during low tide and raised salinities caused a higher concentration of uric acid, while increasing periods of submersion and lowered salinities effected the opposite. Transfer of periwinkles within their intertidal habitat and laboratory experiments to test the effect of salinity showed that the concentration of uric acid in the kidney is adaptable. The dependence of uric acid concentration in the kidney on environmental conditions and the ammoniotelic excretion ofL. littorea are discussed with regard to its particular living conditions. It is suggested that uric acid serves as nitrogen depot and has a particular function in osmoregulation.     

Acute effects on chromium,copper, zinc,and selected clinical variables in urine and serum of male runners

Nine male runners (23-46 yr) ran 6 mi near their maximal pace. Blood and urine samples were obtained prior to, immediately after, and 2 h following the run; 24-h urine collections were also taken on the run and nonrun days. Serum chromium increased significantly (P < 0.05) from 0.12 ± 0.02 (mean ± SE) to 0.17 ± 0.03 ng/mL immediately following running and remained elevated, 0.19 ± 0.03 ng/mL, after 2 h. Urinary chromium concentration was elevated several-fold 2 h following running and daily urinary chromium losses were about twofold higher on the day of the run compared to a rest day. Serum zinc was not significantly different from prerun values immediately following running, 81 ± 4 and 85 ± 4 pμg/dL, respectively, but then decreased significantly to 75 ± 4 2 h after exercise. Urinary zinc concentration was elevated more than twofold 2 h after running and total urinary losses on the day of the run were more than 1.5-fold higher than those on the nonrun day. Serum copper was not altered by exercise. Serum high density lipoprotein (HDL) cholesterol, but not total cholesterol increased significantly following running. HDL cholesterol values were similar to prerun values within 2 h of running. Serum triglycerides, phosphate, creatinine, bilirubin, uric acid, and alkaline phosphatase were also elevated immediately following running, whereas albumin, total protein, and blood urea nitrogen remained constant. These data demonstrate that accompanying the transitory changes in selected clinical indices caused by strenuous running there are alterations in chromium and zinc concentrations in serum and urine and increased specific urinary losses of these essential nutrients.     

Is allantoin in serum and urine a useful indicator of exercise-induced oxidative stress in humans?

To assess whether allantoin levels in serum and urine are influenced by exhaustive and moderate exercise and whether allantoin is a useful indicator of exercise-induced oxidative stress in humans, we made subjects perform exhaustive and moderate (100% and 40% VO₂max) cycling exercise and examined the levels of allantoin, thiobarbituric acid reactive substances (TBARS) and urate in serum and urine. Immediately after exercise at 100% VO₂max, the serum allantoin/urate ratio was significantly elevated compared with the resting levels while the serum urate levels was significantly elevated 30 min after exercise. The serum TBARS levels did not increase significantly compared with the resting levels. Urinary allantoin excretion significantly increased during 60 min of recovery after exercise, however, urinary urate excretion decreased significantly during the same period. The urinary allantoin/urate ratio also rapidly increased during 60 min of recovery after exercise. Urinary TBARS excretion decreased during the first 60 min of the recovery period and thereafter significantly increased during the latter half of the recovery period. On the contrary, after 40% VO₂max of exercise, no significant changes in the levels of urate, allantoin and TBARS in serum or urine were observed. These findings suggest that allantoin levels in serum and urine may reflect the extent of oxidative stress in vivo and that the allantoin which appeared following exercise may have originated not from urate formed as a result of exercise but from urate that previously existed in the body. Furthermore, these findings support the view that allantoin in serum and urine is a more sensitive and reliable indicator of in vivo oxidative stress than lipid peroxidation products measured as TBARS.     

Preconditioning with hydrogen peroxide (H2O2) or ischemia in H2O2-induced cardiac dysfunction

To assess whether allantoin levels in serum and urine are influenced by exhaustive and moderate exercise and whether allantoin is a useful indicator of exercise-induced oxidative stress in humans, we made subjects perform exhaustive and moderate (100% and 40% VO₂max) cycling exercise and examined the levels of allantoin, thiobarbituric acid reactive substances (TBARS) and urate in serum and urine. Immediately after exercise at 100% VO₂max, the serum allantoin/urate ratio was significantly elevated compared with the resting levels while the serum urate levels was significantly elevated 30 min after exercise. The serum TBARS levels did not increase significantly compared with the resting levels. Urinary allantoin excretion significantly increased during 60 min of recovery after exercise, however, urinary urate excretion decreased significantly during the same period. The urinary allantoin/urate ratio also rapidly increased during 60 min of recovery after exercise. Urinary TBARS excretion decreased during the first 60 min of the recovery period and thereafter significantly increased during the latter half of the recovery period. On the contrary, after 40% VO₂max of exercise, no significant changes in the levels of urate, allantoin and TBARS in serum or urine were observed. These findings suggest that allantoin levels in serum and urine may reflect the extent of oxidative stress in vivo and that the allantoin which appeared following exercise may have originated not from urate formed as a result of exercise but from urate that previously existed in the body. Furthermore, these findings support the view that allantoin in serum and urine is a more sensitive and reliable indicator of in vivo oxidative stress than lipid peroxidation products measured as TBARS.     

Temperature and sweating responses in one-legged and two-legged exercise.

In looking at the thermoregulatory responses resulting from symmetrical or asymmetrical exercise, this paper has focused on the effect of local skin temperature (Tsk,local) on local sweat rates (msw,local) during one-legged (W1) and two-legged (W2) exercise on an ergocycle. Five subjects underwent four 3-h tests at 36 degrees C, each consisting of six 25-min exercise periods alternating with 5-min rest periods. The subjects performed W1 and W2 at 45 and 90 W, respectively, either dehydrated or rehydrated. Body temperatures and total sweat rate were measured as well as four msw,local (on chest and thighs), assessed from sweat capsules under which Tsk,local was maintained at predetermined levels (37.0 degrees C and 35.5 degrees C). The combinations of Tsk,local levels, capsule locations, exercise intensity and hydration level chosen in our protocol led to the following results. The hydration level affected rectal temperature but not total or msw,local. No specific effect of muscle activity was found; msw,local on thighs of resting and working legs were similar. The msw,local were only influenced by exercise intensity, msw,local being more elevated during the higher intensity. No significant effect of Tsk,local on msw,local was found, whatever the experimental condition and/or the location. It was concluded that local thermal effects on msw,local could have been masked by the strong central drive for sweating which has been found to exist in subjects exercising in a warm environment.     

Thermoregulatory responses to heat and exercise in Japanese and Caucasians

Responses to heat and exercise were studied in 9 male Japanese subjects who walked on a treadmill at a speed of 4.4 – 4.8 km/h at 0 grade for 2 hours in a climatic chamber in July 1973, in Nagoya Japan. The results were compared with those obtained in a similar study made in July 1966 in Cincinnati, Ohio. The following results were obtained: (1) Japanese showed a 1.8 times higher rate of sweating than Caucasians. Total sweat from the whole body during 2 hours walk was also higher in Japanese. (2) Japanese exhibited lower chloride concentration in local sweat than Caucasians in spite of their higher dietary salt intake, higher serum chloride concentration and higher rate of sweating. While in Caucasians the sweat chloride concentration showed a tendency to continue to rise during the later period of the walk in spite of decreasing sweat rate after sweat suppression occurred, in Japanese it tended to fall in parallel with the sweat rate. No difference was observed in the length of the latent time of sweat suppression. (3) There were no differences in rectal temperature or heart rate, both at the period of equilibrium rectal temperature and at the end of the walk. (4) Mean skin temperature during the walk was significantly higher in Japanese than in Caucasians. It was concluded that the Japanese group was better heat acclimatized than Caucasians, though the two groups were considered to have been naturally heat exposed by season to the same extent.