Urinary citrate excretion in stone-formers and normal controls.

A specific method was used for the estimation of citrate in 24-hour urine collections from 108 young adult controls, 158 patient controls and 164 stone-formers. Stone-formers excreted significantly less citrate in 24 hours than either patient controls or young adult controls. Stone-formers had a lower concentration of citrate in their urine than either of the control groups. The young adult females exhibited a much greater excretion of citrate relative to calcium than the young males. Because of the ability of citrate to complex with calcium ions and keep them in solution, the relatively low incidence of calcium-containing stones in females under 50 years of age could well be the result of their high excretion of citrate and their increased excretion of this substance relative to calcium.     

Reduction of calcium excretion in the stone-forming kidney in unilateral ureteral obstruction

Summary Thirteen urolithiasis patients with unilateral obstructive uropathy were treated with percutaneous nephrostomy (PCN) either for urinary diversion, endopyelotomy, nephrolithtotmy or chemolysis. After percutaneous nephrostomy, the indvidual urine volume, creatinine clearance (Ccr), urinary absolute and fractional excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were measured separately in timed urine collections from a pigtail catheter and from the urethra. The data showed that Ccr and the absolute urinary excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were significantly lower in the PCN kidney immediately or 2 days after relief of obstruction. The ratio of total urinary calcium excretion to urinary creatinine excretion in the obstructed kidney was significantly greater than that in the contralateral kidney. The fractional excretions of calcium and magnesium increased as renal function decreased. The results showed that when the total Ccr is below normal, the apparent excretion of urinary calcium will be underestimated. However, when the total Ccr of patients is within normal range, hypercalciuria may be detected adequately and thus favors early implementation of an appropriate therapeutic strategy.     

Urinary excretion of citrate, glycosaminoglycans, magnesium and zinc in relation to age and sex in normal subjects and in patients who form calcium stones.

One hundred and ninety-seven healthy subjects and 104 patients with idiopathic calcium stone disease had their urinary excretion of citrate, glycosaminoglycans, magnesium, and zinc measured and the results correlated with sex and age. In normal subjects the daily excretion of citrate, magnesium, and zinc increased with age to a maximum during the fifth decade and remained relatively constant until the eighth decade when they decreased. The daily excretion of magnesium and zinc were higher in men than in women, which was attributed to the higher body weights of the men. The urinary excretion of citrate, magnesium, and zinc related to creatinine remained relatively constant with age in adult life; analyses of magnesium and zinc excretion rates divided by urine creatinine did not distinguish men from women. There was no significant difference between men and women for citrate excretion in 24 hour urine, but the citrate:creatinine ratio was significantly higher in women than men. The higher citrate excretion in women may explain the lower incidence of calcium stones in women. The highest glycosaminoglycan excretion rates were seen during the first two decades which is why children and teenagers are less prone to develop calcium stones in spite of high urinary calcium concentrations. Urinary citrate and magnesium excretion were lower, and glycosaminoglycan and zinc excretion were higher, in stone formers than in controls. It seems that a decreased excretion of citrate and magnesium together with an increased excretion of calcium, may contribute to the formation of calcium stones. The role of urinary glycosaminoglycans and zinc in the formation of calcium stones remains uncertain.     

The influence of sex hormones on renal osteopontin expression and urinary constituents in experimental urolithiasis

PURPOSE: To our knowledge the influence of sex hormones on urinary stone formation remains undetermined. We investigated the effect of castration on urinary lithogenic factors and renal osteopontin expression in rats previously treated with ethylene glycol. MATERIALS AND METHODS: Sprague-Dawley rats were divided normal males, castrated males, males with 2 weeks of 0.75% ethylene glycol treatment, castrated males with 2 weeks of 0.75% ethylene glycol treatment, normal females, castrated females, females with 2 weeks of 0.75% ethylene glycol treatment and castrated females with 2 weeks of 0.75% ethylene glycol treatment. We analyzed 24-hour urine samples for urinary constituents, such as calcium, oxalate, citrate, uric acid, phosphate, magnesium, sodium, potassium and creatinine. The kidneys were examined for osteopontin expression by Northern blot analysis and for crystal deposition by histological examination. RESULTS: In intact male rats calcium and citrate excretion decreased and oxalate excretion increased significantly after ethylene glycol treatment. Castrated male rats with ethylene glycol had greater calcium and less oxalate excretion than male intact rats with ethylene glycol. In intact female rats uric acid excretion decreased and only calcium excretion increased significantly after ethylene glycol treatment. Castrated female rats with ethylene glycol excreted significantly more oxalate and less calcium than intact female rats with ethylene glycol. Renal osteopontin expression was the same in male intact and castrated rats, and in female intact and castrated rats. In males with ethylene glycol expression was stronger in castrated than in intact rats. In females with ethylene glycol expression was weaker in castrated than in intact rats. No crystal deposits were found in the kidneys in any group. CONCLUSIONS: Testosterone appears to promote stone formation by suppressing osteopontin expression in the kidneys and increasing urinary oxalate excretion. Estrogen appears to inhibit stone formation by increasing osteopontin expression in the kidneys and decreasing urinary oxalate excretion.     

Studies of urinary risk factors in urolithiasis

Urinary excretions of calcium, oxalate and uric acid were estimated in 160 stone-formers (male 118, female 42) and 257 healthy controls (male 207, female 50). Stone-formers were divided into two groups according to their stone analysis: calcium containing stone-formers and non-calcium stone-formers. Calcium stone-formers were divided again into those who had a single stone episode and multiple or recurrent stone episodes. Urinary calcium and oxalate showed significant increases in calcium stone-formers, while urinary uric acid increased only in male calcium stone-formers. Recurrent calcium stone-formers demonstrated significant high levels of urinary calcium excretion especially in males, whereas no difference of urinary oxalate excretion between recurrent and single stone-formers. The frequency distributions on the excretion of three subjects were estimated respectively in patients with calcium stone and in controls. Relative risks, risk curves and stone probabilities were proposed and compared. The higher excretion values of urinary calcium and oxalate closely related to higher risks of forming calcium stones. On the other hand, urinary uric acid did not have such a relation to calcium stone formation. We defined the states which urinary excretions exceeded 95% upper confidence limits of normal controls as hyperexcretions. Hypercalciuria was more than 200 mg/day in male and female, hyperoxaluria was 50 mg/day in male and 45 mg/day in female and hyperuricosuria was 850 mg/day in male and 650 mg/day in female according to our definition. Among male calcium stone-formers, hypercalciuria was found in 45.3%, hyperoxaluria in 26.4% and hyperuricosuria in 15.1%. While in female calcium stone-formers, hypercalciuria in 23.7%, hyperoxaluria in 26.3% and hyperuricosuria in 13.2%. Of the male calcium stone-formers 57.5% showed either or both hypercalciuria and hyperoxaluria, and recurrent stone-formers also demonstrated a higher incidence among them. Excretion products of urinary calcium and oxalate were calculated and compared in each group. Calcium stone-formers showed significant high values especially in male recurrent stone-formers. The estimation by combining some risk factors will provide more useful means of assessing severity of urinary calculous diseases and therapeutic effects of their various treatments.     

The value of the 24-hour urine analysis in the assessment of stone-formers attending a general hospital outpatient clinic

The daily urinary excretion of calcium, oxalate, uric acid and glycosaminoglycans, and 24-h urinary volume and pH, were measured in 39 normal men and 65 male patients who had formed at least one calcium oxalate stone. No significant difference could be found between the two groups of subjects with respect to any of the urinary parameters. Nonetheless, a higher proportion of stone-formers than normals had daily excretion levels of oxalate in excess of the normal 95th percentile. On the other hand, there was no difference between the proportion of stone-formers and normals who fell into this category with respect to calcium excretion. It was concluded that a single 24-h urine analysis is of limited practical value in explaining the occurrence of stones or in predicting the likelihood of further episodes in unselected stone-formers attending a general hospital outpatient clinic.     

Effects of an acebutolol-hydrochlorothiazide combination on urinary solute excretion in healthy adults

Ten healthy adult male volunteers were studied to assess the urinary effects of a single dose of a combination of hydrochlorothiazide 12.5 mg and acebutolol 200 mg (HZAL). The formation induced a significant increase in the 24-hour urinary output of sodium. Outputs of fluid, chloride, potassium, calcium, magnesium, zinc, total inorganic phosphate and creatinine were unaffected. With the exception of Mg2+ flow, times to maximal urinary flows of fluid and solutes were shortened by HZAL. These qualitative changes resemble those induced by hydrochlorothiazide but did not achieve quantitative significance, either because the constituent diuretic dose was too small or because acebutolol compensated for some of its effects.     

Citrate (CG-120) therapy in urolithiasis. 2. Effect on urinary and serum biochemistry

The long-term effects of citrate therapy (CG-120, 3 g/day or 4 g/day) were examined in 398 patients with upper urinary tract calculi. We studied the influence of citrate therapy on urinary and blood biochemistry in 353 of them. CG-120 caused a sustained increase in urinary citrate, urinary pH and potassium, but no substantial or significant changes in other urinary parameters (uric acid, phosphate, oxalate, sodium, chloride and urine volume). Although urinary calcium decreased significantly up to the 24th week, it did not change significantly there after and it tended to increase at the 54th week. Urinary creatinine excretion decreased after 34 weeks of administration, but this phenomenon could not be explained, because the level of blood urea nitrogen and serum creatinine was not elevated in any case before administration. There were no changes in the serum calcium, magnesium, phosphate, uric acid, sodium, potassium or chloride level.     

Urinary nitrite excretion and urinary variables in patients with primary nocturnal frequency of micturition: effects of indomethacin suppositories

Urinary nitrite excretion was measured in patients with primary nocturnal frequency of micturition (PNFM) and in normal individuals. Effects of indomethacin suppository on urine volume and other urinary variables were evaluated. The study comprised seven patients with PNFM and seven healthy control (age range 30–45 years). Nitrite was assayed in spot morning urine samples; urine volume, urine osmolality and electrolytes, serum osmolality and electrolytes and functional bladder capacity (FBC) were assayed. Both groups were then given 100 mg of indomethacin suppository daily for a maximum of 10 days and urinary variables were re-evaluated during day 10. Results showed that urinary nitrite excretion of patients with PNFM was greater than that of the normal subjects (230±62 umol/l vs. 42±30 umol/l, P<0.05). The mean (SD) 24 h urine volume and osmolality, the night urine volume and osmolality, serum osmolality, FBC, creatinine clearance, fractional excretion of sodium (FENa), fractional excretion of potassium (FEK), and urinary excretion of glucose and potassium were lower in patients with PNFM as compared with normal individuals, although not statistically significantly so, except for FBC that was significantly lower in the patients. Urinary excretion of sodium, calcium, chloride, phosphorus, magnesium, day-night urinary volume ratio, spot morning osmolality, nocturnal index, and nocturnal polyuria index were higher in patients with PNFM. Indomethacin decreased the 24 h urinary volume by 21%, creatinine clearance by 12%, osmolar clearance by 14% and urinary protein excretion by 38% in the patients. These variables decreased by 26, 45, 17 and 12% respectively in the healthy subjects, whereas 24 h urinary protein excretion increased mildly by 9%. Indomethacin increased day-night urinary volume ratio by 73% in the healthy subjects. It might be concluded that urinary nitrite excretion, urinary excretion of sodium, chloride, phosphorus, calcium, and magnesium increased and FBC decreased in patients with PNFM; Indomethacin decreased urinary volume, FENa, FEK, osmolar clearance, and free water clearance in the healthy subjects and the patients. These might explain the mechanism of action of indomethacin to reduce frequency of voiding. The possible interaction of prostaglandin and NO in the pathogenesis of PNFM is discussed.     

Silicon metabolism. I. Some aspects of renal silicon handling in normal man

Renal silicon handling was investigated in 23 healthy adults using electrothermal atomic absorption techniques. The mean urinary silicon excretion was 33.1 +/- 3.85 mg/day; the mean renal silicon clearance was 88.6 +/- 7.94 ml/min; the mean fractional excretion of silicon was 86.35 +/- 8.1%, and the mean urine silicon concentration was 0.265 micrograms/ml. Using multiple correlation analysis, the urinary silicon was found to be highly significantly correlated with the urine magnesium concentration (p less than 0.001) and also with urinary sodium and urinary osmolality (p less than 0.01). 24-hour urinary silicon excretion was highly significantly correlated with fractional excretion of silicon (p less than 0.001), sodium (p less than 0.001), phosphorus (p less than 0.001), magnesium (p less than 0.001), and osmolar load. In split urine studies in 7 subjects urinary silicon was correlated highly significantly with urinary magnesium in all 7 and with urinary osmolality, urine calcium, and urine creatine concentration in 6 of 7. There was a highly significant correlation between renal silicon clearance and fractional excretion of silicon (p less than 0.0005), with magnesium excretion (p less than 0.01), and with sodium excretion. It is suggested that ion pairing of orthosilicate and magnesium may explain some of these urinary findings.     

Pattern of urolithiasis in a general hospital a prospective study

Judging from the abundance of papers published in the medical journals there appears to be a global increase in the incidence of urolithiasis. Urinary excretion of various stone-forming salts in a 24-hour urine specimen is the mainstay of the metabolic workup done in stone-formers. According to the findings patients have been classified into neat categories depending on whether they were hypercalciuric, hyperuriocosuric, etc. As a group their excretion of calcium, oxalate, and urate was not different from the controls. However, they excreted significantly more phosphate and had lower 24-hour urine volumes than the controls.     

Familial hypokalemia-hypomagnesemia or Gitelman's syndrome: a further case.

A woman aged 33 years presented hypokalemia and hypomagnesemia associated with renal potassium and magnesium wasting. Her mean 24-hour urinary calcium excretion was strikingly low despite normocalcemia, normal creatinine clearance, normal serum PTH and calcitriol. Normal distal fractional chloride reabsorption [CH2O/(CH2O + CCl)] was noted during water load but was reduced during hypotonic saline infusion. In response to intravenous furosemide (1 mg/kg), the patient showed significant increments in sodium, chloride and magnesium excretion as well as abolition of hypocalciuria. The association of renal calcium transport from magnesium transport together with exaggerated natriuresis after furosemide suggests the presence of a defect in the distal tubule rather than in the loop of Henle. We propose that our patient is affected by the syndrome of primary renotubular hypomagnesemia-hypokalemia with hypocalciuria, known as Gitelman's syndrome.     

Circadian rhythms of lithogenic and inhibitory substances in the urine

The diurnal variations of urine composition with respect to urinary pH, volume, creatinine, calcium, magnesium, phosphate, uric acid, citrate and oxalate were studied in five healthy men. Generally, there was considerable variations in the excretion of the different urine constituents with meal related peaks except phosphate, which was most pronounced after dinner. The analysis of a 24-hour urine collection cannot account fully for the crystallization properties of urine and a fractionated urinalysis might be of value for therapeutic decisions. However, such procedures probably will not be possible in clinical practice and more reliable methods for evaluation of the crystallization propensity in whole 24-hour urine have to be developed.     

Adequacy of a single stone risk analysis in the medical evaluation of urolithiasis

PURPOSE: We tested the hypothesis that a single 24-hour urine sample for stone risk analysis would be sufficient for the simplified medical evaluation of urolithiasis. MATERIALS AND METHODS: We retrospectively analyzed stone risk profile data on 24-hour urine samples obtained during random and restricted diets in 225 patients with recurrent urolithiasis. RESULTS: In 2 random samples we noted no significant difference in urinary calcium, oxalate, uric acid, citrate, pH, total volume, sodium, potassium, sulfate or phosphorus. For these risk factors there was a highly significant positive correlation in the 2 random samples (r > or = 0.68, p <0.0003) and the value of each was abnormal or normal in at least 81% of patients. Urinary magnesium and ammonium were significantly lower in random sample 2 than 1, the former by 4%. After calcium, sodium and oxalate dietary restriction mean urinary calcium and sodium plus or minus standard deviation decreased significantly by 25% from 251 +/- 125 to 187 +/- 98 mg. daily and by 38% from 183 +/- 87 to 113 +/- 57 mEq. daily, respectively. Other risk factors had a slight or no significant change. Correcting random urinary calcium for the excessive urinary excretion of sodium brought urinary calcium to 210 +/- 108 mg. daily, similar to the value on the restricted diet. CONCLUSIONS: The reproducibility of urinary stone risk factors is satisfactory in repeat urine samples. A single stone risk analysis is sufficient for the simplified medical evaluation of urolithiasis.     

Diurnal rhythm of urinary calcium excretion in adults

Twenty-four-hour urinary calcium excretion is normally the equivalent of daily calcium intake, and varies between 200-300 mg/dL with a calcium/creatinine ratio of 0.07-0.15. In this study, we aimed to investigate the diurnal rhythm of calcium excretion in healthy individual. Forty subjects (30 male, 10 female) were involved into the study. The spot urine samples were taken at 08:00, 14:00, and 22:00 together with a 24-hour collection. Mean spot urinary calcium levels at 08:00, 14:00, and 22:00 were 12.39 +/- 8.19, 12.97 +/- 8.37, and 16.95 +/- 10.39 mg/dL, with calcium/creatinine ratios of 0.104 +/- 5.261, 0.119 +/- 7.85, and 0.133 +/- 8.17, respectively. Twenty-four-hour urinary calcium excretion was 12.74 +/- 7.31 mg/dL with a calcium/creatinine ratio of 0.111 +/- 5.41. The values at 08:00, 14:00, and of 24-hour collection were statistically similar (p > 0.05), but the nighttime values were significantly elevated (p < 0.05). In conclusion, calcium excretion is increased at night, and urinary calcium measurements should be interpreted accordingly.     

Effect of animal and vegetable protein intake on oxalate excretion in idiopathic calcium stone disease

Oxalate excretion was measured in healthy subjects and idiopathic calcium stone-formers on dietary regimens which differed in the type and amount of protein allowed; 24-h urine collections were obtained from 41 practising vegetarians and 40 normal persons on a free, mixed, "mediterranean" diet. Twenty idiopathic calcium stone-formers were also studied while on two low calcium, low oxalate diets which differed in that animal protein was high in one and restricted in the other. Vegetarians had higher urinary oxalate levels than controls and although the calcium levels were markedly lower, urinary saturation with calcium/oxalate was significantly higher. This mild hypercalciuria was interpreted as being secondary to both a higher intake and increased fractional intestinal absorption of oxalate. Changing calcium stone-formers from a high to a low animal protein intake produced a significant decrease in calcium excretion but there was no variation in urinary oxalate. As a result, the decrease in calcium oxalate saturation was only marginal and not significant. It was concluded that dietary animal protein has a minimal effect on oxalate excretion. Mild hyperoxaluria of idiopathic calcium stone disease is likely to be intestinal in origin. Calcium stone-formers should be advised to avoid an excess of animal protein but the risks of a vegetable-rich diet should also be borne in mind.     

Urinary excretion of minerals, oxalate, and uric acid in north Indian children

Urinary excretion of calcium, magnesium, phosphate, uric acid, oxalate, and creatinine was measured in 208 children (aged 8 – 15 years, 124 boys, 84 girls), living in a residential school near New Delhi. Levels were reduced compared with those reported from developed countries. The 95th percentile value of 24-h creatinine excretion was 33.4 mg/kg, calcium 2.2 mg/kg, magnesium 2.9 mg/kg, phosphate 9.4 mg/kg, uric acid 4.4 mg/kg, and oxalate 1.5 mg/kg. The 95th percentile value of the urine calcium/creatinine ratio was 0.15 and oxalate/creatinine 0.06. The dietary intake of proteins, calcium, and other nutrients in these children was less than recommended and explained the reduced urinary excretion observed. Physicians need to be aware of the regional patterns of normal urinary excretion of these constituents. Received November 30, 1995; received in revised form and accepted October 24, 1996     

Increased urinary nitrite excretion in primary enuresis: effects of indomethacin treatment on urinary and serum osmolality and electrolytes,urinary volumes and nitrite excretion

OBJECTIVE: To assess urinary nitrite excretion, a stable end product of nitric oxide (NO), in patients with enuresis and in normal controls, and to evaluate the effects of indomethacin (a potent prostaglandin synthesis inhibitor) on urinary nitrite excretion, other urinary variables and bladder capacity. PATIENTS AND METHODS: The study comprised 10 patients with primary enuresis and 10 normal comparable controls (age range 6-14 years). Nitrite was assayed in 'spot' morning urine samples in both the enuretics and normal controls. Enuretics were then given 50 mg indomethacin suppositories each night; urine volume, urinary osmolality and electrolytes, serum osmolality and electrolytes and urinary nitrite were assayed before indomethacin treatment and after 15 days of treatment. RESULTS: The mean (sd) urinary nitrite excretion was 24.4 (19.6) micromol/L in normal children and 275.9 (111.2) micromol/L in enuretics (P<0.05). With indomethacin, the urinary nitrite concentration was significantly decreased to 141 (45.1) micromol/L (P<0.05) and associated with a significant reduction in bed-wetting episodes and voiding frequency. The functional bladder capacity was <70% of the predicted value for age in six of the patients; they had significant improvements on indomethacin, to values similar to those in patients with a nearly normal functional bladder capacity. Indomethacin decreased the 24-h urinary volume by 41%, the night volume by 40%, clearance of free water by 46% and increased the day : night urinary volume ratio by 55%. The absolute amounts of urinary calcium, magnesium, phosphorus, urea, creatinine, and glucose were lower on indomethacin, although not statistically significantly so. Indomethacin decreased the 24-h urinary and 'spot' morning osmolality and osmotic clearance. There were no significant changes in serum osmolality and electrolyte concentrations. Indomethacin also decreased the absolute amount of urinary sodium, chloride and potassium, fractional sodium and potassium excretion, and filtered sodium. Creatinine clearance was decreased by 20% (P>0.05) and normal 24-h urinary protein was significantly lower, by 47%, after indomethacin treatment (P<0.05). CONCLUSION: Urinary nitrite excretion increased significantly in patients with primary nocturnal enuresis; indomethacin markedly reduced bed-wetting episodes and decreased the frequency of voiding in enuretics with small or normal functional bladder capacity, which was associated with a significant decrease in urinary nitrite excretion. Indomethacin reduced bed-wetting by decreasing the urine volume, clearance of free water and urinary electrolytes, and through possible effects on bladder and urethral contraction, by inhibiting NO and prostaglandin synthesis. NO and prostaglandins might be important in the pathogenesis of primary enuresis.     

Tacrolimus-associated hypomagnesemia in renal transplant recipients

BACKGROUND: Since hypomagnesemia occurs frequently in tacrolimus treated patients, we studied the correlation between renal magnesium wasting and tacrolimus blood levels in renal transplant patients. METHODS: Serum magnesium, fractional excretion of magnesium (FEMg), and 24-hour urinary excretion of magnesium were measured in 41 transplant patients and 10 healthy volunteers for correlation with tacrolimus level. RESULTS: Of tacrolimus-treated patients, 43% displayed hypomagnesemia. FEMg (7.42+/-3.59% versus 1.88+/-0.43%) and 24-hour urinary excretion (112.36+/-51.43 mg/dL versus 6.7+/-2.79 mg/dL) were significantly higher among tacrolimus-treated patients than controls. Magnesium replacement did not influence FEMg or 24-hour urinary magnesium excretion. Tacrolimus level was the best predictor of 24-hour urinary magnesium excretion and FEMg. Serum magnesium levels correlated inversely with tacrolimus concentrations and creatinine clearance. CONCLUSION: Hypomagnesemia in renal transplant recipients results from renal magnesium wasting. Tacrolimus levels and renal function impact on the excess renal magnesium excretion. Studies of longer duration are warranted to assess the long-term effects of this early posttransplant hypomagnesemia.     

Short-term effects of desmopressin on water and electrolyte excretion in adults with nocturnal polyuria

PURPOSE: Increased calcium excretion due to desmopressin has been reported in children with nocturnal enuresis. Desmopressin is often used to treat adult patients with nocturnal polyuria. However, data on the effect of desmopressin on water/electrolyte excretion in adults are scarce. We present the short-term effects of desmopressin on water and electrolyte excretion in adult patients with nocturnal polyuria. MATERIALS AND METHODS: A total of 16 male patients with nocturnal polyuria, mean age 76.3 years, received 0.1 or 0.2 mg desmopressin before sleep. Frequency volume chart was recorded, and daytime and nighttime urine samples were collected separately before and after desmopressin administration. Urinary excretions of sodium, potassium and calcium were determined, and compared before and after treatment with desmopressin. RESULTS: Desmopressin significantly increased urine osmolality, decreased nocturnal total urine volume, reduced the ratio of nocturnal urine volume-to-whole day urine volume and decreased nocturnal voiding frequency. Nocturnal urinary excretion of calcium (mean 0.137 vs 0.169 mg/kg body weight per hour, p = 0.004) and whole day excretion of calcium (mean 165.9 vs 200.0 mg per day, p = 0.012) were increased after desmopressin treatment. Nocturnal urinary potassium excretion (mean 0.030 vs 0.025 mEq/kg body weight per hour, p = 0.030) and whole day potassium excretion (mean 40.7 vs 36.1 mEq per day, p = 0.017) were decreased by desmopressin treatment. However, desmopressin treatment did not significantly change urinary secretion of sodium and chloride at nighttime or for the whole day. CONCLUSIONS: Desmopressin reduces nocturnal urine volume and nocturnal voiding frequency in male patients with nocturnal polyuria. However, increased calcium and decreased potassium excretion following desmopressin treatment deserve attention particularly when it is used on a long-term basis.