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At least 19 recordsLinked to original sources
PubMed1983

Relationship of urinary kallikrein excretion to renal water and sodium excretion.

The circadian rhythms of urine volume and urinary excretion of sodium, potassium, kallikrein, and aldosterone were analyzed by a multivariate method (cosinor method) in 20 healthy Japanese women on an ordinary diet. The relationship of urinary kallikrein and aldosterone excretion to urine volume and urinary sodium and potassium excretion was studied by assessing the correlation of the circadian rhythms. The acrophases in the circadian rhythms of urine volume (16:51) and urinary sodium excretion (16:55) appeared after the acrophase of urinary kallikrein excretion (15:28). There was a highly significant correlation between the circadian rhythm of urinary kallikrein excretion and the circadian rhythms of urine volume (r = 0.948) and urinary sodium excretion (r = 0.921). These results suggest that the renal kallikrein-kinin system participates in the regulation of renal water and sodium excretion in persons on an ordinary diet. A highly significant relationship between the acrophases in the circadian rhythms of urine volume and sodium excretion (r = 0.935) also suggests that water and sodium excretion may have a mutual influence on the kidneys. There were positive correlations between the circadian rhythms of potassium excretion and kallikrein excretion and potassium excretion and sodium excretion; and the latter relationship was relatively closer than the former. The acrophase in the circadian rhythm of aldosterone excretion did not correlate well with the acrophases of the other urine variables including sodium excretion.

Adult↗
PubMed1997

Urinary excretion of epidermal growth factor and Tamm-Horsfall protein in three rat models with increased renal excretion of urine.

Epidermal growth factor (EGF) and Tamm-Horsfall protein (THP) are synthesized in the kidneys by the distal tubular cells and excreted into urine. The urinary excretion of these peptides has been suggested as a potential index for distal tubular function. The urinary excretion rates of EGF and THP were examined in three groups of rats with increased renal excretion of urine: uninephrectomy, non-osmotic polyuria and diabetic osmotic polyuria. Twenty-four hour urine samples were obtained after 7, 14 and 21 days. The urinary volume per kidney was doubled in uninephrectomy when compared to controls. There was a seven-fold increase in urinary volume in rats with non-osmotic polyuria and diabetic osmotic polyuria, as compared to controls. Uninephrectomy, non-osmotic polyuria and diabetes all affected the urinary excretion of EGF and THP differently. The EGF excretion in uninephrectomized rats was 60-80% of that of the controls, whereas THP excretion was unchanged, indicating that EGF excretion varied with renal tissue mass. Non-osmotic polyuria caused a five-fold increase in THP excretion but no change in EGF excretion. THP excretion in the diabetic rats was increased three-fold after 21 days when compared to controls, whereas EGF excretion was decreased when expressed per kidney weight. Immunohistochemistry demonstrated that EGF and THP were colocalized in the thick ascending limbs of Henle's loops and distal tubules in all five groups of rats. In conclusion, the EGF excretion appears to follow renal tissue mass and seems independent of urinary volume, whereas THP excretion is dependent mainly on urinary volume. This has implications for the use of EGF and/or THP excretion rates as an indicator for distal tubular function.

Adjuvants, Immunologic↗
PubMed1991

Comparison of fractional excretion and 24-hour urinary excretion of sodium and potassium in clinically normal cats and cats with induced chronic renal failure.

The influence of induced chronic renal failure on 24-hour urinary excretion and fractional excretion of sodium and potassium was studied in cats. Induction of chronic renal failure significantly increased fractional excretion of potassium (P less than 0.0001) and sodium (P less than 0.05); however, 24-hour urinary excretion of sodium and potassium decreased slightly following induction of chronic renal failure. Fractional excretion and 24-hour urinary excretion of sodium and potassium were compared by linear regression in clinically normal cats, cats with chronic renal failure, and clinically normal and affected cats combined. In clinically normal cats, linear regression revealed only moderate correlation between fractional excretion and 24-hour urinary excretion for sodium and potassium. Linear regression of these same relationships in cats with chronic renal failure, and in clinically normal cats and cats with chronic renal failure combined, indicated low correlation. Fractional excretions of sodium and potassium were not reliable indicators of 24-hour urinary excretion of these electrolytes in cats with chronic renal failure or unknown glomerular filtration rate. Fractional excretion of potassium and sodium correlated only moderately with 24-hour urinary excretion in clinically normal cats.

Animals↗
PubMed2001

Urinary excretion of the aquaporin-2 water channel exaggerated in pathological states of impaired water excretion.

OBJECTIVE: The present study was undertaken to determine whether the hydro-osmotic action of arginine vasopressin (AVP) is exaggerated in pathological states of impaired water excretion by measuring urinary excretion of the aquaporin-2 (AQP-2) water channel. PATIENTS AND MEASUREMENTS: Eighteen hyponatraemic patients with impaired water excretion and 12 control subjects were studied during an acute oral water load (20 ml/kg body weight). RESULTS: In the patient group plasma AVP levels were 1.6 pmol/l, relatively high compared to plasma osmolality of 279.8 mmol/kg. Urinary excretion of AQP-2 under ad libitum water drinking was 41.1 fmol/micromol creatinine in the patient group, a value significantly greater than that of 21.7 fmol/micromol creatinine in the control subjects. The acute water load verified the impairment in water excretion in the patient group, as the excretion of the water load was only 28.2% (control, 77.3%, P < 0.001) and the minimum urinary osmolality was as high as 437.3 mmol/kg (control, 122.9 mmol/kg, P < 0.001). Also, the minimum urinary excretion of AQP-2 was significantly greater in the patient group than that in the control. There was a positive correlation between plasma AVP levels and urinary excretion of AQP-2 in the control subjects (r = 0.56, P < 0.01). In contrast, the urinary excretion of AQP-2 was exaggerated compared to the respective plasma AVP levels in the patient group, and thus the positive correlation disappeared. CONCLUSION: These results indicate that hydroosmotic action of AVP is exaggerated more than that expected from plasma AVP levels in pathological states of impaired water excretion, with non-suppressible, but normal, arginine vasopressin levels in spite of the hypo-osmotic condition.

Aged↗
PubMedDate not supplied

Alkaline environmental pH has no effect on ammonia excretion in the mudskipper Periophthalmodon schlosseri but inhibits ammonia excretion in the related species Boleophthalmus boddaerti.

Experiments were performed to evaluate the effects of alkaline environmental pH on urea and ammonia excretion rates and on tissue urea, ammonia, and free amino acid concentrations in two mudskippers, Periophthalmodon schlosseri and Boleophthalmus boddaerti. Periophthalomodon schlosseri is known to be capable of actively excreting ammonia. The rate of ammonia excretion in B. boddaerti exposed to 50% seawater (brackish water, BW) at pH 9 decreased significantly during the first 2 d of exposure when compared with that of specimens exposed to pH 7 or 8. This suggested that B. boddaerti was dependent on NH(3) diffusion for ammonia excretion, as in most fishes. It was incapable of detoxifying the accumulating endogenous ammonia to urea but could store and tolerate high concentrations of ammonia in the muscle, liver, and plasma. It did not undergo reductions in proteolysis and/or amino acid catabolism in alkaline water, probably because the buildup of endogenous ammonia was essential for the recovery of the normal rate of ammonia excretion by the third day of exposure to a pH 9 medium. Unlike B. boddaerti, P. schlosseri did not accumulate ammonia in the body at an alkaline pH (i.e., pH 9) because it was capable of actively excreting ammonia. Periophthalmodon schlosseri did not undergo partial amino acid catabolism (no accumulation of alanine) either, although there might be a slight reduction in amino acid catabolism in general. The significant decrease in blood pCO(2) in B. boddaerti at pH 9 might lead to respiratory alkalosis in the blood. In contrast, P. schlosseri was able to maintain its blood pH in BW at pH 9 despite a decrease in pCO(2) in the blood. With 8 mM NH(4)Cl in BW at pH 7, both mudskippers could actively excrete ammonia, although not to the same extent. Only P. schlosseri could sustain ammonia excretion against 8 mM NH(4)Cl in BW at pH 8. In BW containing 8 mM NH(4)Cl at pH 9, both mudskippers died within a short period of time. Boleophthalmus boddaerti consistently died faster than did P. schlosseri. This indicates that the body surfaces of these mudskippers were permeable to NH(3), but the skin of P. schlosseri might be less permeable to NH(3) than that of B. boddaerti. Both mudskippers excreted acid (H(+)) to alter the pH of the alkaline external medium. Such a capability, together with modifications in gill morphology and morphometry as in P. schlosseri, might be essential to the development of an effective mechanism for the active excretion of NH+4.

Acid-Base Equilibrium↗
PubMed1975

The relationship between kallikrein and water excretion and the conditional relationship between kallikrein and sodium excretion.

1. The renal kallikrein-kinin system has previously been linked with renal control of sodium and water excretion. The present investigations were carried out to examine more closely these relationships. 2. In physiological studies with rabbits, urinary kallikrein was measured by a modification of the [3-H]TAME method. 3. With rabbits on free sodium and water intake, urinary kallikrein was positively correlated with both sodium and water excretion. Kallikrein excretion was also negatively correlated with urinary osmolality. 4. In rabbits on chronic high and low sodium diets, urinary kallikrein was positively correlated with urinary volume but not with sodium excretion. 5. In rabbits held to a constant fluid intake but with sodium intake changed, urinary kallikrein was not correlated with sodium excretion. 6. These results indicate that the positive correlation of kallikrein excretion with sodium excretion under conditions of free sodium and water intake may be only secondary to the positive relationship of kallikrein excretion with urinary volume. 7. The results of the present investigations do not support the hypothesis that the renal kallikrein-kinin system is necessarily involved in renal control of sodium excretion under normal conditions but it is where a change in sodium intake leads to a change in fluid intake and consequently of urinary volume. 8. In the above experiments, urinary kallikrein was always positively correlated with urinary volume and negatively correlated with urinary osmolality. This may indicate a functional relationship between renal kallikrein and water excretion.

Animals↗
PubMed1990

Diurnal variation in water, sodium and potassium excretion in primary glomerulonephritic patients and its relation to diurnal kallikrein excretion.

In order to investigate whether or not primary glomerulonephritic patients have abnormal diurnal water, sodium, and potassium excretion and its relation to diurnal urinary kallikrein excretion (UKE)., we studied the diurnal patterns of urinary water, sodium, potassium, and kallikrein excretion in 16 primary glomerulonephritic patients and 12 normal persons. Urinary kallikrein activity was measured by the enzymatic hydrolysis of synthetic chromogenic substrate S-2266, and urinary electrolytes were measured by flame photometry. The day, night, and 24-hour urine outputs were significantly higher in glomerulonephritic patients, but urinary sodium, potassium and kallikrein excretion at all periods of collection did not differ between glomerulonephritic patients and normal controls. UKE was positively correlated with urinary potassium excretion in both normal controls (r = 0.5, p less than 0.05) and glomerulonephritic patients (r = 0.66, p less than 0.01), whereas no correlation existed between UKE and urinary water excretion, or UKE and urinary sodium excretion in either group. The day/night output ratio of water, sodium and potassium excretion were not different between glomerulonephritic patients and normal subjects. These results indicate that: (1) there is no abnormal diurnal water, sodium, potassium, and kallikrein excretion in primary glomerulonephritic patients with fair renal function; and (2) urinary kallikrein may play a role in the regulation of urinary potassium excretion.

Adult↗
PubMed2000

Biliary copper excretion capacity in intact animals: correlation between ATP7B function, hepatic mass, and biliary copper excretion.

Copper toxicosis can occur in the absence of biliary copper excretion. To demonstrate whether biliary copper excretion capacity is correlated with hepatic mass and ATP7B function, we undertook studies in intact animals. Copper-histidine was injected intrasplenically after baseline bile collection, followed by measurement of copper excretion in Long-Evans Cinnamon (LEC) rats lacking atp7b function and in normal, syngeneic Long-Evans Agouti (LEA) rats. The basal biliary copper excretion was very low in LEC rats compared with LEA rats, 8+/-4 and 37+/-18 ng copper/min, respectively; p<0.05. After addition of copper, copper excretion increased significantly (by two- to five-fold) in LEA rats during the 30 minute study period, whereas LEC rats showed only a slight and transient increase in copper excretion. After one-third and two-thirds partial hepatectomy immediately before copper loading, copper excretion decreased progressively. The studies indicate that biliary copper excretion depends on hepatocyte mass and ATP7B gene function. Analysis of copper excretion with our non-radioactive method will facilitate testing of novel therapies and pathophysiological mechanisms in copper toxicity.

Adenosine Triphosphatases↗
PubMed1988

Relation between renal and hepatic excretion of drugs: X. Excretion of nalorphine in young and adult rats pretreated with hormones or xenobiotics.

Different processes are involved in renal and hepatic excretion of organic anions and cations. In contrast to our knowledge of anion excretion, information about cation transport in kidney and liver is relatively scarce. In this study, the elimination of nalorphine was investigated to characterize the relation between renal and hepatic excretion of organic cations. Nalorphine is excreted effectively both via kidney and liver. However, its hepatic excretion dominates in adult rats. In young, 20-day-old animals biliary nalorphine elimination is immature and the excreted amounts are significantly lower. Renal excretion of nalorphine is quite similar in rats of both ages. After bile duct ligation renal excretion of nalorphine increases significantly in adult rats whereas it remains unchanged in young ones. Remarkably, after bilateral nephrectomy hepatic elimination of nalorphine is even diminished in both age groups. In further experiments renal excretion of nalorphine could be stimulated in adult rats after repeated administration of trometamol, triiodothyronine, or dexamethasone; these treatments had no consequences on biliary secretion of nalorphine.

Aging↗
PubMed2000

Influence of curcumin on cyclosporin-induced reduction of biliary bilirubin and cholesterol excretion and on biliary excretion of cyclosporin and its metabolites.

We investigated the ability of curcumin, which can be extracted from different Curcuma species, to prevent cyclosporin-induced reduction of biliary bilirubin and cholesterol excretion, and its influence on biliary excretion of cyclosporin (CS) and its metabolites in the bile fistula model in rats. I.v. injection of curcumin (25 and 50 mg/kg) after 30 min increased dose-dependently basal bile flow (30 microliters/kg/min) up to 200%, biliary bilirubin excretion (3000 pmol/kg/min) up to 150%, and biliary cholesterol excretion (22 nmol/kg/min) up to 113%. CS (30 mg/kg) reduced bile flow to 66% and biliary excretion of bilirubin and of cholesterol to 33% of the basal value 30 min after i.v. injection. I.v. administration of curcumin (25 and 50 mg/kg) 30 min after CS increased bile flow dose dependently again to 130% for 1 hour and biliary excretion of cholesterol and of bilirubin to 100% of the basal value for 30 and 150 min, respectively. Injection of curcumin 15 min before CS prevented the CS-induced drop of bile flow at 50 mg/kg and reduction of biliary bilirubin excretion already at 25 mg/kg until the end of the experiment (180 min). The CS-induced reduction of biliary cholesterol excretion, however, was not prevented by curcumin. Finally, the biliary excretions of CS (1200 ng/kg/min) and its metabolites (1200 ng/kg/min) were slightly reduced by curcumin at a dose of 50 mg/kg (to 83% of the initial values). The clinical importance of these controversial effects remains to be shown.

Animals↗
PubMed1990

Urinary excretion of polyamines: importance of circadian rhythm, age, sex, menstrual cycle, weight, and creatinine excretion.

The urinary excretion of putrescine, spermidine, spermine, and N1- and N8-acetylspermidines was measured in 95 volunteers. The 24-h excretion, split in four consecutive periods, was analyzed for circadian rhythm in eight volunteers. Circadian rhythm was observed in total polyamine and in N1- and N8-acetylspermidine excretions. The excretion rates of these polyamines were highest in the morning. The normal values for 24-h urinary excretion of polyamines were determined in 87 volunteers. Men excreted significantly more spermidine (P less than 0.001), N8-acetylspermidine (P less than 0.05), and spermine (P less than 0.001) than did women; putrescine excretion was higher in women (P less than 0.001). This variation was only partially explained by differences between sexes in body or muscle mass because most differences remained significant even after normalization for creatinine excretion and body weight. No correlation between the polyamine excretions and age or menstrual cycle was found.

Adult↗
PubMed1994

Endothelin excretion in hypertensive pregnancy. Relationship to glomerular filtration rate, blood pressure, and sodium excretion.

The objective of this study was to determine whether urinary endothelin (ET) excretion is altered in pregnant women with preeclampsia or essential hypertension compared with normal pregnant and nonpregnant women, and whether urinary ET excretion is significantly related to glomerular filtration rate (GFR), blood pressure, or sodium excretion in hypertensive pregnant women. Subjects included 85 hypertensive women in their third trimester (32 with severe preeclampsia, 37 with mild preeclampsia [some of whom may be classified as having "transient (gestational) hypertension" by other classifications], and 16 with essential hypertension), 42 normal third-trimester pregnant women, and 26 normal nonpregnant women. Twenty-four-hour urine ET and creatinine excretion were measured in all women. ET was extracted from urine and measured by radioimmunoassay. Plasma creatinine, serum uric acid and albumin concentrations, and urine protein and sodium excretion were also measured. Twenty-four-hour ET excretion was significantly higher (P < .01) in normal pregnant women (14.7 [9.1 to 20.1] pmol/day; median [interquartile range]) than in nonpregnant women (8.4 [6.4 to 15.2] pmol/day) and was reduced significantly (P < .01) in hypertensive pregnant women (severe preeclampsia: 9.0 [5.5 to 12.4] pmol/day; mild preeclampsia: 7.2 [5.7 to 9.9] pmol/day; essential hypertension: 7.5 [6.4 to 9.4] pmol/day) compared to values for normal pregnant women. Twenty-four-hour urine ET excretion in hypertensive pregnant women was correlated positively but weakly with both creatinine clearance (r = 0.31, P < .01) and urine sodium excretion (r = 0.34, P < .01). Urinary ET excretion is increased in normal pregnancy and reduced from these values in pregnancies complicated with preeclampsia or essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMedDate not supplied

Urinary albumin excretion in children: factors related to elevated excretion in the United States population.

Past population studies have indicated a higher prevalence of high albumin excretion in children than in adults. In this study, NHANES III United States population data was analyzed to study factors associated with elevated albumin excretion in children 8 to 18 years of age. The analysis confirmed a higher prevalence of albumin values > 30 mg/g creatinine and > 200 mg/g creatinine in children than in adults, and indicated that girls are two to three times more likely to have albumin excretion above these levels than boys. Neither hypertension nor reported diabetes--major factors influencing albumin excretion in adults--accounted for the higher excretion levels in children. The higher excretion levels were not associated with prescription medications or a poor rating of the child's overall health status by a physician. The higher prevalences is influenced by puberty stage and is more likely to occur in children with lower than average body mass index, independent of the relationship with urine creatinine excretion. The increased prevalence of high albumin excretion is probably associated with normal development in children, but an increased susceptibility to chronic diseases in the future among the children with high excretion cannot be ruled out.

Adolescent↗
PubMed1987

Relationship of urinary kallikrein excretion to urinary potassium excretion during furosemide administration with and without amiloride.

The relationship of urinary kallikrein excretion to urine volume, and to urinary sodium and potassium excretions was studied in normal rats during furosemide diuresis and superimposed injection of amiloride, a K+-sparing diuretic. Continuous infusion of furosemide increased urinary kallikrein, sodium and potassium excretions and the urine volume. Amiloride injection during furosemide diuresis caused further increase in diuresis and natriuresis, but a prompt decrease in urinary kallikrein excretion to basal level, and potassium excretion to below the basal level. The significant correlation of urinary kallikrein excretion to urinary potassium excretion, but not to urine volume and urinary sodium excretion after amiloride injection suggests that the major determinant of urinary kallikrein excretion is renal potassium secretion through a mechanism that is affected by amiloride.

Amiloride↗
PubMed1995

Impaired biliary excretion and whole body elimination of methylmercury in rats with congenital defect in biliary glutathione excretion.

Biliary excretion of methylmercury, a major route of elimination of this toxic compound, was less than 2% of control in Eisai hyperbilirubinemic (EHBR) rats, a mutant Sprague-Dawley strain with a defect in biliary excretion of a variety of organic anions, including glutathione S-conjugates and reduced glutathione (GSH). Biliary GSH excretion in EHBR rats was also < 2% of controls, confirming previous findings. Impaired biliary methylmercury and GSH excretion was not explained by decreased hepatic content of these compounds. Indeed, hepatic methylmercury and GSH concentrations in EHBR rats were actually double those of controls. To assess the significance of the impaired biliary excretion in the whole body elimination of the toxicant, 203Hg excretion was measured over a 17-day period after intraperitoneal administration of either 0.5 or 5 mumol/kg of 203Hg-methylmercury chloride. The results for the two doses were similar. Methylmercury was eliminated by a first order process; however, the biological half-line was significantly longer in the EHBR rats, 46 to 54 days versus 18 to 22 days. Fecal excretion was the main route of elimination in both control and mutant animals. At necropsy (17 days), 16% to 25% of the 203Hg dose was recovered in the liver of the EHBR rats, whereas livers of control animals contained less than 2%of the administered dose. These findings demonstrate the biliary excretion of methylmercury is markedly impaired in EHBR rats and is associated with a low biliary GSH excretion, providing support for the hypothesis that methylmercury is normally transported across the canalicular membrane by a GSH-dependent mechanism, and presumably as a GSH mercaptide (CH3Hg-SG).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Urinary creatinine excretion in the ICU: low excretion does not mean inadequate collection.

BACKGROUND: It has been assumed that a urinary creatinine excretion rate of less than 10 mg/kg per day means an inadequately collected urine sample. OBJECTIVE: To determine the frequency of a urinary creatinine excretion rate of less than 10 mg/kg per day in intensive care unit patients with an adequately collected urine sample. METHOD: In a prospective study of creatinine excretion rates, 24-hour urine samples were evaluated for urinary creatinine in 209 critically ill patients with indwelling Foley catheters. Patients from three adult intensive care units in New York City were divided into two groups. Group 1 patients excreted less than 10 mg/kg per day of urinary creatinine, and group 2 patients excreted at least 10 mg/kg per day. Groups 1 and 2 were first evaluated by dividing the creatinine excretion data by actual body weight. Since actual body weight may overestimate body weight in the critically ill patient, data from groups 1 and 2 were also evaluated using lean body weight. RESULTS: Urinary creatinine excretion was less than 10 mg/kg per day in 36.8% of patients using actual body weight and 29.7% of patients adjusted for lean body weight. The average age of patients in group 1 was 74 +/- 17 years for both actual body weight and lean body weight. The average age of group 2 patients was 60 +/- 19 years for actual body weight and 62 +/- 19 years for lean body weight. There was a significant difference in age between group 1 and group 2 patients for both actual body weight and lean body weight. The proportion of female vs male patients with reduced creatinine excretion was significantly greater, whether the actual body weight or lean body weight adjustment was used. CONCLUSIONS: A urinary creatinine excretion rate of less than 10 mg/kg per day occurs in about one third of critically ill patients, who are more likely to be elderly and female.

Adult↗
PubMed1996

High sodium intake increases the urinary excretion of L-3,4-dihydroxyphenylalanine but fails to alter the urinary excretion of dopamine and amine metabolites in Wistar rats.

1. The present study has examined the daily urinary excretion of L-DOPA, dopamine and its metabolites (DOPAC, 3-MT and HVA) during normal salt (NS) and high salt(HS) diets. 2. Daily urinary excretion of L-DOPA, DA, DOPAC, 3-MT and HVA during the 4-day period of NS diet averaged, respectively, 7.6 +/- 0.4, 71 +/- 5, 217 +/- 22, 570 +/- 90 and 1217 +/- 110 nmol/kg/day. The slight increase in the urinary excretion of DA, DOPAC and 3-MT (16% to 42% increase), when rats were fed a HS diet, did not achieve statistical significance. 3. In contrast, the urinary levels of L-DOPA during the HS diet period (11 +/- 1 nmol/kg/day) were found to be significantly higher than during the NS diet period; the maximal increase in the urinary excretion of L-DOPA (93% increase) was observed in the first day and then a progressive decline was observed towards the end of the HS intake period. 4. During the first 5 days of the HS intake period, the urine output of noradrenaline (NA) was found to increase (27% to 83%) and then to progressively decline to baseline values (13.5 +/- 0.7 nmol/ kg/day). Urinary excretion of adrenaline (AD) during the HS intake period was found to increase (72% to 146%); the mean daily urinary excretion of AD during the NS diet period averaged 2.5 +/- 0.4 nmol/ kg/day. NS and DA contents in the kidney of rats on a NS diet were not significantly different from that of rats in a HS diet. 6. It is concluded that long-term HS intake in Wistar rats fail to change the urinary excretion of DA and of its metabolites (DOPAC, 3-MT and HVA). Furthermore, the discrepant profile in the urinary excretion of L-DOPA and DA during HS intake might be related to a reduction in the tubular uptake of the amino acid, rather than reflecting a decrease in its decarboxylation.

3,4-Dihydroxyphenylacetic Acid↗