Query: excretion of dilute urine

title: HPLC MS/MS analysis of anthocyanins in human plasma and urine using protein precipitation and dilute and shoot sample preparation methods, respectively.
abstract: A high performance liquid chromatography tandem mass spectrometry (HPLC MS/MS) method has been developed to analyze anthocyanins in urine and plasma to further understand their absorption, distribution, metabolism and excretion. The method employed a Synergi RP Max column (250 x 4.6 mm, 4 mm) and an API 4000 mass spectrometer. A gradient elution system consisted of mobile phase A (water 1% formic acid) and mobile phase B (acetonitrile) with a flow rate of 0.60 mL/min. The gradient was initiated at 5% B, increased to 21% B at 20 min, and then increased to 40% B at 35 min. The analysis of anthocyanins presents a challenge because of the poor stability of anthocyanins during sample preparation, especially during solvent evaporation. In this method, the degradation of anthocyanins was minimized using protein precipitation and dilute and shoot and sample preparation methods for plasma and urine, respectively. No interferences were observed from endogenous compounds. The method has been used to analyze anthocyanin concentrations in urine and plasma samples from volunteers administered saskatoon berries. Cyanidin 3 galactoside, cyanidin 3 glucoside, cyanidin 3 arabinoside, cyanidin 3 xyloside and quercetin 3 galactoside, the five major flavonoid components in saskatoon berries, were identified in plasma and urine samples.

title: Nonoxidative glucose metabolism a prerequisite for formation of dilute urine.
abstract: To examine links between norepinephrine (NE) stimulated sodium transport and gluconeogenesis, we perfused isolated rat kidneys with 6% albumin, containing various combinations of glucose, alanine, pyruvate. and lactate and inhibitors of gluconeogenesis (0.1 mM mercaptopicolinate, MP) or glucose metabolism (0.2 0.5 mM 2 deoxyglucose, DG) Inulin clearance, fractional potassium reabsorption, total sodium reabsorption, and free water clearance were higher in kidneys perfused with 5 mM glucose plus 2 mM alanine than in kidneys perfused with either 10 mM lactate or 5 mM pyruvate. NE, added after 40 min of perfusion, decreased fractional sodium and potassium excretion in all experiments. In lactate and/or pyruvate perfused kidneys NE decreased fractional water excretion with little increase in free water clearance; free water formation was lowest in kidneys perfused with DG or MP. Glucose (5 mM) reversed the inhibitory effect of MP on free water clearance. In glucose perfused kidneys NE did not decrease fractional water excretion, whereas free water clearance increased threefold. NE stimulated glucose production from pyruvate 2.4 fold and from lactate 1.6 fold. MP inhibited gluconeogenesis both in the basal state and after NE. We conclude that the formation of dilute urine requires nonoxidative glucose metabolism to maintain low water permeability in the diluting segment and a high peritubular glucose concentration that is ensured by gluconeogenesis in adjacent proximal tubules.

title: Increasing dietary sodium chloride promotes urine dilution and decreases struvite and calcium oxalate relative supersaturation in healthy dogs and cats
abstract: Urolithiasis is highly prevalent in dogs and cats, with struvite and calcium oxalate being most commonly diagnosed. Some commercial diets aimed at reducing the risk of urolithiasis are based on inclusion of sodium chloride (NaCl) in an attempt to dilute the urine and the risk of crystallization, but more information on the effect of differing levels of sodium inclusion is needed. The objective of this study was to compare the short term effect of four diets differing only in NaCl content (base diet with 0.3% sodium and diets with added NaCl to achieve 0.7, 1.0 and 1.3% sodium as fed) on urinary ion concentrations and relative supersaturation (RSS) of struvite and calcium oxalate in dogs and cats. In both species, there was a significant increase in water intake and urine volume as dietary NaCl increased. Urine sodium concentration increased with increasing dietary NaCl. The highest sodium diet increased urinary calcium excretion in dogs only, while decreasing urinary calcium concentration. Calcium oxalate RSS and struvite RSS both significantly decreased, with the lowest RSS values reported on the highest sodium diet in both dogs and cats (p .001) These results suggest that an increase in dietary NaCl decreases RSS values in both dogs and cats. Despite an increase in urinary calcium excretion in dogs, urinary calcium concentration and calcium oxalate RSS were lower on high sodium diets due to urine dilution. Long term studies are needed to confirm the relationship between RSS and stone occurrence and recurrence.

title: Effect of acute water loading on plasma levels of antidiuretic hormone AVP aldosterone, ANP fractional excretion of sodium and plasma and urine osmolalities in myxedema.
abstract: We monitored the plasma and urine osmolalities, fractional excretion of sodium, fractional excretion of chloride, plasma levels of antidiuretic hormone (ADH, AVP) aldosterone and atrial natriuretic peptide (ANP) before and after acute water ingestion in 12 patients with overt hypothyroidism. The ability of the patients to dilute and concentrate urine was found impaired and the ability of excretion of water load decreased and delayed. Acute water load test was proved to be effective in evaluating the urinary excreting function for the patients. We hypothesize that inappropriate secretion of anti diuretic hormone and elevated plasma ANP may be homeostatic factors for abnormal urinary excretion in patients with hypothyroidism.

title: Lomerizine, trimetazidine and bis (4 fluorophenyl) methylpiperazine in human urine after oral administration of lomerizine dihydrochloride: analysis by liquid chromatography high resolution tandem mass spectrometry.
abstract: In sports drugs testing, the differentiation between the abuse of the prohibited substance trimetazidine and that of the permitted drug lomerizine is required because trimetazidine is one of the metabolites of lomerizine. Therefore, it is important to identify a lomerizine specific metabolite in urine that allows making the distinction. In this study, a simple dilute and shoot method employing liquid chromatography high resolution tandem mass spectrometry for the quantification of trimetazidine, lomerizine and the specific metabolite bis (4 fluorophenyl) methylpiperazine (M6) in urine was developed. An oral dose of 15 mg was administered to 10 male volunteers, after which urine samples collected during the following 276 hours were analyzed using the developed method, allowing for examination of the target analytes' excretion profile. The limit of detection of all target analytes was <0.02 ng/mL. In all volunteers, the metabolite M6 was detected up to 276 hours after administration. After more than 12 hours, all volunteers were found to have higher concentrations of the metabolite M6 than of trimetazidine. The concentrations of trimetazidine, lomerizine, M6, and the M6/trimetazidine ratio in the final sample collected after 276 hours were 0.2 0.9 ng/mL, <0.05 0.1 ng/mL, 14.1 38.3 ng/mL, and 28.8 122.9, respectively. The urinary excretion of trimetazidine, unchanged lomerizine, and the metabolite M6 within the first 276 hours was 0.64% 0.006% and 6.1% respectively. Consequently, the absence of the metabolite M6 in doping control urine samples corroborates the conclusion that lomerizine is unlikely to be the source of trimetazidine. The results confirm that the M6 metabolite is the longest lasting urinary metabolite of lomerizine currently known.

title: Impact of solute intake on urine flow and water excretion.
abstract: It is classically taught that when renal function is normal and the secretion of antidiuretic hormone (arginine vasopressin) is fully suppressed, the human kidney has the capacity to excrete large volumes of dilute urine, allowing for a broad range of water intake. This flexibility protects against the development of hyponatremia even in the face of water intake that can approach 20 L/d. What is not as widely recognized is the impact that alterations in solute intake, and therefore excretion, have on this process. As will be illustrated here, a decrement in solute intake markedly reduces the above mentioned flexibility and puts the individual at risk for the unexpected development of hyponatremia. In contrast, an increment in solute intake can be used therapeutically to treat this electrolyte disorder and allow those prone to it to liberalize their water intake.

title: Urinary detection of conjugated and unconjugated anabolic steroids by dilute and shoot liquid chromatography high resolution mass spectrometry.
abstract: Anabolic androgenic steroids (AAS) are an important class of doping agents. The metabolism of these substances is generally very extensive and includes phase I and phase II pathways. In this work, a comprehensive detection of these metabolites is described using a 2 fold dilution of urine and subsequent analysis by liquid chromatography high resolution mass spectrometry (LC HRMS) The method was applied to study 32 different metabolites, excreted free or conjugated (glucuronide or sulfate) which permit the detection of misuse of at least 21 anabolic steroids. The method has been fully validated for 21 target compounds (8 glucuronide, 1 sulfate and 12 free steroids) and 18 out of 21 compounds had detection limits in the range of 1 10 ng mL( 1) in urine. For the conjugated compounds, for which no reference standards are available, metabolites were synthesized in vitro or excretion studies were investigated. The detection limits for these compounds ranged between 0.5 and 18 ng mL( 1) in urine. The simple and straightforward methodology complements the traditional methods based on hydrolysis, liquid liquid extraction, derivatization and analysis by gas chromatography mass spectrometry (GC MS) and liquid chromatography mass spectrometry (LC MS)

title: THE ABSORPTION AND EXCRETION OF WATER AND SALTS BY MARINE TELEOSTS
abstract: It is a peculiar and interesting fact that marine teleosts excrete urine which is isotonic or hypotonic with respect to the blood, and therefore of considerably lower osmotic pressure than sea water (Rodier, 1899; Bottazzi, 1906; Dekhuyzen, 1905; Burian, 1908, 1910) From this, it appears that these animals are faced with the task of concentrating the surrounding ocean in order to obtain water for the formation of urine, a task which can only be performed at the expenditure of energy in osmotic work. This circumstance might be expected to result in profound differences in the water economy of marine fish as compared with fresh water and terrestial animals to which water is available ad k&turn. The answer to the question of what tissue or tissues actually do the work of separating from the sea water the osmotically dilute solution destined to be excreted as urine appears to rest in the determination of whether the renally excreted water is initially absorbed from the intestine or enters the body through the gills. The work to be reported here leads us to the conclusion that water absorption occurs by way of the intestine; but, surprisingly, it is not in the intestine that the osmotic work is done, for the residue formed there as absorption proceeds is actually more dilute than the ingested sea water, and tends to approach the blood in tonicity. This osmotic dilution results from the fact that Na, K and Cl are absorbed from the intestine, along with a considerable fraction of the water, leaving behind only the poorly absorbed Mg and SO4 in highly concentrated state. During this process of concentration some Mg and SO4 are abosrbed, to be subsequently excreted in the urine. The bulk of the Na, K and Cl, together with the bulk of the water absorbed from the intestine, never appear in the urine, however; they are excreted by routes other than the kidneys

title: Hyperaldosteronism after decreased renal K+ excretion in KCNMB2 knockout mice.
abstract: The kidney is the primary organ ensuring K( homeostasis. K( is secreted into the urine in the distal tubule by two mechanisms: by the renal outer medullary K( channel (Kir1.1) and by the Ca(2+ activated K( channel (KCa1.1) Here, we report a novel knockout mouse of the b2 subunit of the KCa1.1 channel (KCNMB2) which displays hyperaldosteronism after decreased renal K( excretion. KCNMB2( mice displayed hyperaldosteronism, normal plasma K( concentration, and produced dilute urine with decreased K( concentration. The normokalemia indicated that hyperaldosteronism did not result from primary aldosteronism. Activation of the renin angiotensin aldosterone system was also ruled out as renal renin mRNA expression was reduced in KCNMB2( mice. Renal K( excretion rates were similar in the two genotypes; however, KCNMB2( mice required elevated plasma aldosterone to achieve K( balance. Blockade of the mineralocorticoid receptor with eplerenone triggered mild hyperkalemia and unmasked reduced renal K( excretion in KCNMB2( mice. Knockout mice for the a subunit of the KCa1.1 channel (KCNMA1( mice) have hyperaldosteronism, are hypertensive, and lack flow induced K( secretion. KCNMB2( mice share the phenotypic traits of normokalemia and hyperaldosteronism with KCNMA1( mice but were normotensive and displayed intact flow induced K( secretion. Despite elevated plasma aldosterone, KNCMB2( mice did not display salt sensitive hypertension and were able to decrease plasma aldosterone on a high Na( diet, although plasma aldosterone remained elevated in KCNMB2( mice. In summary, KCNMB2( mice have a reduced ability to excrete K( into the urine but achieve K( balance through an aldosterone mediated, b2 independent mechanism. The phenotype of KCNMB2 mice was similar but milder than the phenotype of KCNMA1( mice.

title: Effect of abrupt change in the salinity of the environment on plasma electrolytes, urine volume, and electrolyte excretion in channel catfish, Ictalurus punctatus
abstract: Na levels of fish transferred from fresh water to salt water remained hypernatremic to the environment; however, plasma Cl remained at or near the environmental level. 2. 2. Acclimation in salt water hyperionic to plasma ions required 15 days; in a medium isonatremic and hyperchloremic acclimation required 3 days, but in isoionic medium no change in plasma ions occurred. 3. 3. Handling did not affect plasma Na and Cl of fresh water fish. 4. 4. Acclimation in isoionic salt water had no effect on the response of plasma electrolytes to a hyperionic medium. 5. 5. Plasma Na and Cl decreased significantly after transfer from salt to fresh water. 6. 6. Fish in salt water produced small amounts of concentrated urine hypoosmotic to the plasma, compared to the large volume of dilute urine produced by fish in fresh water.