A simple assessment of the effect of strontium on the urinary excretion of calcium in Sprague Dawley rats.

This study was aimed at investigating the impact of varying concentrations of strontium (Sr) on calcium (Ca) excretion via the urine and determine its impact on kidney stone formation. Twenty adult male Sprague Dawley rats weighing between 200 and 300 g were selected. The rats were randomly divided into four groups of five. One group was used as a control group while the other three groups were experimental. The diet of the rats was modulated over a 12 week period to investigate the impact of Sr on the urinary excretion of Ca. Urinary samples were collected every 2 weeks from the rats. The rats were fed water ad libitum. After the study the rats were euthanised and their kidneys harvested. Urine and kidney samples from the rats were analysed using Total Reflection X-Ray Fluorescence (TXRF). In the urine excretion of Ca increased with increased intake of Sr in the diet. Sr excretion via the urine also increased with increased dietary intake. There was a correlation of 0.835 at the significance level of 0.01 between Ca and Sr in the urine. However, for the kidneys, the varying concentration of Sr did not impact the retention of Ca in the kidneys. There was increased retention of Sr in the kidneys with increased dietary intake. In this study an increase of Sr in the diet resulted in an increase in urinary excretion of Ca.

Association of Urinary Strontium Levels with Pregnancy-induced Hypertension.

Pregnancy-induced hypertension (PIH), including gestational hypertension and preeclampsia, accounts for the majority of maternal and perinatal morbidity and mortality. Strontium (Sr) has been recently associated with preeclampsia in a small group of women; however, the role of Sr in PIH is not fully understood and warrants further investigation. In this study, we examined the association between urinary Sr levels and PIH, and assessed the effect of maternal age on the association. Urinary Sr concentrations were measured in 5423 pregnant women before delivery by inductively coupled plasma mass spectrometry (ICP-MS). Logistic regression analysis adjusting for potential confounders was applied to explore the association between Sr and PIH, and to evaluate the Sr-PIH relationship stratified by maternal age. Among the participants, 200 (3.83%) women were diagnosed with PIH. Compared with non-PIH women, women who developed PIH had lower urinary Sr concentrations (131.26 vs. 174.98 µg/L creatinine, P<0.01). With the natural log-transformed urinary creatinine-standardized Sr concentrations increasing, the risk of PIH decreased significantly [adjusted OR=0.60 (95%CI: 0.51, 0.72)]. Furthermore, the significant association of Sr with PIH was found among women under 35 years (P<0.01). Our finding suggested that Sr may play a potential protective role in the pathogenesis of PIH, especially among young pregnant women under 35 years old.

Urinary biomarker of strontium exposure is positively associated with semen quality among men from an infertility clinic.

Experimental studies have shown that nonradioactive strontium (Sr), in the form of Sr2+, have a positive effect on semen quality, but human evidence is lacking. This study aimed to examine the associations between nonradioactive Sr exposure and semen quality in Chinese men (n = 394). We recruited men who presented at an infertility clinic in Wuhan, China to seek for semen parameter analyses. Urinary Sr concentration as an exposure biomarker was measured using inductively coupled plasma mass spectrometer. We estimated the associations between urinary Sr concentrations and semen parameters using multivariable logistic and linear regression models. In multivariable linear regressions models, positive dose-response associations were estimated for sperm concentration, motility, and count across increasing urinary Sr quartiles (all p for trends<0.05), and the consistent positive associations were also observed for urinary Sr concentration modeled as a continuous exposure. In multivariable logistic models, decreased risks of below-reference sperm concentration, motility, and count were also estimated across increasing urinary Sr quartiles (all p for trends<0.05). Our results suggest that nonradioactive Sr exposure may have a beneficial effect on semen quality, but more investigations are warranted to confirm the results.

Effect of a maximal exercise test on serum and urinary concentrations of magnesium, phosphorous, rubidium and strontium in athletes.

AIM: This study aims to determine the changes induced by a maximal exercise test until exhaustion on the serum and urinary concentrations of Magnesium (Mg), Phosphorous (P), Rubidium (Rb) and Strontium (Sr) in athletes (AG) and sedentary students (SG). METHODS: Fifty subjects participated in the study divided into two groups. In AG there were twenty-five male athletes and in SG there were twenty-five male sedentary students. Both groups performed an exercise test until exhaustion, starting at 8 or 10 km/h respectively, and increasing the speed at 1 km/h every 400 m. Serum and urine samples were obtained from all participants before and after the test. RESULTS: Regarding the basal status, AG showed lower values of Mg in serum (p < 0.05) and urine (p < 0.01), but higher concentrations of serum P (p < 0.05) in comparison to SG. Comparing the pre and post-test values, corrected or non-corrected for hemoconcentration in serum and for creatinine in urine, AG showed a decrease in serum Mg (p < 0.05), in serum P (p < 0.01) and in urinary Sr (p < 0.01) while an increase was observed in urinary P (p < 0.05) and in urinary Rb (p < 0.05). CONCLUSIONS: It can be concluded that a treadmill test until exhaustion leads to changes in serum and urinary concentrations of minerals in both AG and SG males. This may reflect an adaptive response of the body to overcome the physical stress and, in some cases, to avoid loss of these elements.

Association of plasma and urine metals levels with kidney function: A population-based cross-sectional study in China.

OBJECTIVES: Although environmental exposure to multiple metals is common, epidemiological studies on the associations of exposure to 23 metals with kidney function have not been analyzed. We aimed to investigate the associations of 23 metals levels with renal function. METHODS: We conducted a cross-sectional study in four rural regions of Hunan province. Plasma and urine metals levels were determined by inductively coupled plasma mass spectrometer (ICP-MS). Two-level logistic regression was used to investigate the associations of metals levels with estimated glomerular filtration rate (eGFR) with adjustment for confounding factors. We conducted a sensitivity analysis of the results using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. RESULTS: A total of 3553 participants completed the investigation. Five metals (plasma arsenic and molybdenum; urine copper, rubidium, and strontium) were identified to be significantly associated with renal function. Participants in the highest quartile of plasma arsenic and molybdenum were at 17.95 (95% CI: 6.35-50.76) and 24.23 (95% CI: 7.42-79.19) fold risk of abnormal eGFR, respectively, compared with the lowest quartile. The highest quartiles of urine copper, rubidium, and strontium were associated with 3.70 (95% CI:1.92-7.14), 0.16 (95% CI:0.07-0.37) and 0.08 (95% CI: 0.03-0.21) fold risk of abnormal eGFR. The sensitivity analysis revealed that plasma arsenic, molybdenum and urine copper, rubidium and strontium levels retained similar associations with abnormal eGFR. CONCLUSION: Plasma arsenic and molybdenum, and urine copper are risk factors for abnormal renal function, while urine rubidium and strontium are protective factors for renal function.

Intestinal Calcium Absorption among Hypercalciuric Patients with or without Calcium Kidney Stones.

BACKGROUND AND OBJECTIVES: Idiopathic hypercalciuria is a frequent defect in calcium kidney stone formers that is associated with high intestinal calcium absorption and osteopenia. Characteristics distinguishing hypercalciuric stone formers from hypercalciuric patients without kidney stone history (HNSFs) are unknown and were explored in our study. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We compared 172 hypercalciuric stone formers with 36 HNSFs retrospectively selected from patients referred to outpatient clinics of the San Raffaele Hospital in Milan from 1998 to 2003. Calcium metabolism and lumbar bone mineral density were analyzed in these patients. A strontium oral load test was performed: strontium was measured in 240-minute urine and serum 30, 60, and 240 minutes after strontium ingestion; serum strontium concentration-time curve and renal strontium clearance were evaluated to estimate absorption and excretion of divalent cations. RESULTS: Serum strontium concentration-time curve (P<0.001) and strontium clearance (4.9±1.3 versus 3.5±2.7 ml/min; P<0.001) were higher in hypercalciuric stone formers than HNSFs, respectively. The serum strontium-time curve was also higher in hypercalciuric stone formers with low bone mineral density (n=42) than in hypercalciuric stone formers with normal bone mineral density (n=130; P=0.03) and HNSFs with low (n=22; P=0.01) or normal bone mineral density (n=14; P=0.02). Strontium clearance was greater in hypercalciuric stone formers with normal bone mineral density (5.3±3.4 ml/min) than in hypercalciuric stone formers and HNSFs with low bone mineral density (3.6±2.5 and 3.1±2.5 ml/min, respectively; P=0.03). Multivariate regression analyses displayed that strontium absorption at 30 minutes was positively associated calcium excretion (P=0.03) and negatively associated with lumbar bone mineral density z score (P=0.001) in hypercalciuric stone formers; furthermore, hypercalciuric patients in the highest quartile of strontium absorption had increased stone production risk (odds ratio, 5.06; 95% confidence interval, 1.2 to 20.9; P=0.03). CONCLUSIONS: High calcium absorption in duodenum and jejunum may expose hypercalciuric patients to the risk of stones because of increased postprandial calcium concentrations in urine and tubular fluid. High calcium absorption may identify patients at risk of bone loss among stone formers.

[Determination of strontium content in whole blood and urine by icp-ms].

Parameters of strontium determination in the whole blood and urine of children living near ore deposits containing up to 20% strontium sulfate have been determined. The average strontium content in the whole blood of two children groups of 109.52 ± 11.07 mg/L and 131.62 ± 12.95 mg/L, significantly exceeded the level in the comparison group 44.2 ± 4.24 mg/L. The average strontium contents of two groups of children in urine were 1252.3 ± 332.2 mg/L and 1341.5 ± 241.8 mg/L, these values were 4.2 and 4.5 times higher than in the comparison group 296.4 ± 61.5 mg/L. The conditions for blood and urine sample preparation were optimized to reduce measure errors and to determine strontium at the reference concentration level. The accuracy of the results has been confirmed by analysis of the standard samples Seronorm™ Whole Blood L1, L2, L3 and Seronorm™ Urine.

Low Serum Testosterone Levels Are Associated with Elevated Urinary Mandelic Acid, and Strontium Levels in Adult Men According to the US 2011-2012 National Health and Nutrition Examination Survey.

BACKGROUND: Little is known regarding the effects of environmental exposure of chemicals on androgenic system in the general population. We studied 5,107 subjects included in the National Health and Nutrition Examination Survey (2011-2012). METHODS: Urinary, serum, and blood levels of 15 subclasses comprising 110 individual chemicals were analyzed for their association with serum testosterone levels. The subjects were divided into high and low testosterone groups according to the median testosterone concentration (374.51 ng/dL). Odds ratios (ORs) of individual chemicals in association with testosterone were estimated using logistic regression after adjusting for age, ethnicity, cotinine, body mass index, creatinine, alcohol, and the poverty income ratio. RESULTS: Adjusted ORs for the highest versus lowest quartiles of exposure were 2.12 (95% CI: 1.07, 4.21; Ptrend = 0.044), 1.84 (95% CI: 1.02, 3.34; Ptrend = 0.018) for the association between urinary mandelic acid, and strontium quartiles with low testosterone concentrations in adult men, respectively. However, no association was observed for the remaining chemicals with testosterone. CONCLUSIONS: The National Health and Nutrition Examination Survey data suggest that elevations in urinary mandelic acid, and strontium levels are negatively related to low serum testosterone levels in adult men.

[Distribution of rubidium, cesium, beryllium, strontium, and barium in blood and urine in general Chinese population].

OBJECTIVE: To investigate the distribution of rubidium (Rb), cesium (Cs), beryllium (Be), strontium (Sr), and barium (Ba) in blood and urine in general Chinese population. METHODS: A total of 18 120 subjects aged 6~60 years were enrolled from 24 regions in 8 provinces in Eastern, Central, and Western China from 2009 to 2010 based on the method of cluster random sampling. Questionnaire survey was conducted to collect the data on living environment and health status. Blood and urine samples were collected from these subjects, and the levels of Rb, Cs, Be, Sr, and Ba in these samples were determined by inductively coupled plasma mass spectrometry. The distribution of these elements in blood and urine in male or female subjects living in different regions was analyzed statistically. RESULTS: In the general Chinese population, the concentration of Be in the whole blood was below the detection limit (0.06 µg/L); the geometric mean (GM) of Ba in the whole blood was below the detection limit (0.45 µg/L), with the 95th percentile (P95)of 1.37 µg/L; the GMs (95% CI)of Rb, Cs, and Sr in the whole blood were 2 374(2 357~2 392) µg/L, 2.01 (1.98~2.05) µg/L, and 23.5 (23.3~23.7) µg/L, respectively; in males and females, the GMs (95%CI)of blood Rb, Cs, and Sr were 2 506 (2 478~2 533) µg/L and 2 248 (2 227~2 270) µg/L, 1.88 (1.83~1.94) µg/L and 2.16 (2.11~2.20) µg/L, and 23.4 (23.1~23.7) µg/L and 23.6 (23.3~23.9) µg/L, respectively(P<0.01, P>0.05, and P>0.05). In the general Chinese population, the GM of urine Be was below the detection limit (0.06 µg/L), while the GMs (95%CI)of urine Rb, Cs, Sr, and Ba were 854 (836~873) µg/L, 3.65 (3.56~3.74) µg/L, 39.5 (38.4~40.6) µg/L, and 1.10 (1.07~1.12) µg/L, respectively; in males and females, the GMs (95%CI)of urine Rb, Cs, Sr, and Ba were 876 (849~904) µg/L and 832 (807~858) µg/L, 3.83 (3.70~3.96) µg/L and 3.47 (3.35~3.60) µg/L, 42.5 (40.9~44.2) µg/L and 36.6 (35.1~38.0) µg/L, and 1.15 (1.12~1.19) µg/L and 1.04 (1.01~1.07) µg/L, respectively (all P< 0.01). Correlation analyses showed that there were weak correlations between blood Rb and urine Rb (r=0.197)and between blood Sr and urine Sr (r=0.180), but a good correlation between blood Cs and urine Cs (r=0.487). CONCLUSION: The levels of Rb, Cs, Be, Sr, and Ba in the general Chinese population are similar to those reported in other countries, and there is a significant difference in the concentration of each element among the populations living in different regions, as well as significant differences in blood Rb, urine Rb, urine Cs, urine Sr, and urine Ba between males and females.

Comparison of Barium and Arsenic Concentrations in Well Drinking Water and in Human Body Samples and a Novel Remediation System for These Elements in Well Drinking Water.

Health risk for well drinking water is a worldwide problem. Our recent studies showed increased toxicity by exposure to barium alone (≤700 µg/L) and coexposure to barium (137 µg/L) and arsenic (225 µg/L). The present edition of WHO health-based guidelines for drinking water revised in 2011 has maintained the values of arsenic (10 µg/L) and barium (700 µg/L), but not elements such as manganese, iron and zinc. Nevertheless, there have been very few studies on barium in drinking water and human samples. This study showed significant correlations between levels of arsenic and barium, but not its homologous elements (magnesium, calcium and strontium), in urine, toenail and hair samples obtained from residents of Jessore, Bangladesh. Significant correlation between levels of arsenic and barium in well drinking water and levels in human urine, toenail and hair samples were also observed. Based on these results, a high-performance and low-cost adsorbent composed of a hydrotalcite-like compound for barium and arsenic was developed. The adsorbent reduced levels of barium and arsenic from well water in Bangladesh and Vietnam to <7 µg/L within 1 min. Thus, we have showed levels of arsenic and barium in humans and propose a novel remediation system.

Urinary strontium and the risk of breast cancer: a case-control study in Guangzhou, China.

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) µg/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

High Zn content of Randall's plaque: a µ-X-ray fluorescence investigation.

Kidney stone disease, or nephrolithiasis, is a common ailment. Among the different risk factors usually associated with nephrolithiasis are dehydration, metabolic defects (especially with regard to calcium and oxalate). The presence of a mineral deposit at the surface of the renal papilla (termed Randall's plaque) has all been recently underlined. Of note, Randall's plaque is made of the calcium phosphate, carbapatite, and serves as a nucleus for kidney stone formation. The process by which apatite nanocrystals nucleate and form Randall's plaque remains unclear. This paper deals with the possible relationship between trace elements and the formation of this mineral. The investigation has been performed on a set of Randall's plaques, extracted from human kidney stones, through µ-X-ray diffraction and µ-X-ray fluorescence analyses in order to determine the chemical composition of the plaque as well as the nature and the amount of trace elements. Our data provide evidence that Zn levels are dramatically increased in carbapatite of RP by comparison to carbapatite in kidney stones, suggesting that calcified deposits within the medullar interstitium are a pathological process involving a tissue reaction. Further studies, perhaps including the investigation of biomarkers for inflammation, are necessary for clarifying the role of Zn in Randall's plaque formation.

Rapid methods for the isolation of actinides Sr, Tc and Po from raw urine.

Rapid methods for the isolation and analysis of individual actinides (Th, U, Pu, Am/Cm) and Sr, Tc and Po from small volumes of raw urine have been developed. The methods involve acidification of the sample and the addition of aluminum nitrate or aluminum chloride salting-out agent prior to isolation of the desired analyte using a tandem combination of prefilter material and extraction chromatographic resin. The method has been applied to the separation of individual analytes from spiked urine samples. Analytes were recovered in high yield and radionuclide purity with separation times as low as 30 min. The chemistry employed is compatible with automation on the ARSIIe instrument.

Human biokinetics of strontium--part II: Final data evaluation of intestinal absorption and urinary excretion of strontium in human subjects after stable tracer administration.

Fractional intestinal absorption (f1 value) and urinary excretion of strontium in healthy human volunteers has been measured by simultaneous oral and intravenous administration of the stable isotopes 86Sr and 84Sr using the double-isotope method. Final evaluation of the complete data set confirmed that ingestion of different foodstuff and nutritional factors could influence the fractional gut uptake of strontium. In some cases, significant deviations from the f1 value adopted by the International Commission on Radiological Protection (ICRP) were found. The arithmetic mean (+/- standard deviation) of the f1 values of all experiments performed was determined to be 0.46 (+/- 0.24). The probability distribution function of the f1 values is represented by a lognormal curve with a geometric mean of 0.38 and a geometric standard deviation of 2.06. Urinary excretion in all subjects varied depending on the administered foodstuff in a wide range and differs from the ICRP model, up to 2 days after tracer administration. No age or gender dependence of the absorbed strontium fraction and of the urinary excretion of strontium after an oral load was found.

[Determination of the contents of fourteen elements in urine of Xinjiang kuitun fluorine poisoning and arsenic-fluoride poisoning patients by ICP-AES].

A method of determining the contents of K, Na, Ca, Mg, P, Zn, Al, Ba, Co, Cu, Ni, Sr, Cr and Ti, fourteen elements, in urine of Xinjiang Kuitun fluorine poisoning and arsenic-fluoride poisoning patients was developed. The operation conditions of ICP-AES, and the lowest test concentration, precision and linear ranges were studied. The relative standard deviation of the method was 0.24%-2.47% (n=10), the average recoveries were 90.4%-00.5%. The contents of K and Na in urine of fluorine poisoning and arsenic-fluoride poisoning patients were higher than those of healthy contrast group. The contents of Ba, Co, Cu, Ni and Cr in the urine of arsenic-fluoride poisoning patients were higher than those of fluorine poisoning patients and healthy contrast group (P < 0.05). The contents of P, Ca, Mg, Zn, Al, Sr and Ti do not have statistic significance (P > 0.05). The method was sensitive, simple and accurate. The experiment data was reliable.

Assessment of intakes of mixtures of radionuclides.

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.

Lactose does not enhance calcium bioavailability in lactose-tolerant, healthy adults.

BACKGROUND: There is evidence from animal studies that lactose has a beneficial effect on intestinal calcium absorption. However, data concerning the effect of lactose on calcium absorption in lactose-tolerant adults are inconclusive. OBJECTIVE: Our objective was to investigate the effect of lactose on calcium bioavailability in humans by the use of a stable-strontium test under controlled metabolic conditions. DESIGN: Eleven healthy, lactose-tolerant subjects (8 women, 3 men) randomly received a bolus of 2.27 mmol strontium alone (load A), the bolus with 35 g lactose (load B), or the bolus with 17.5 g glucose and 17.5 g galactose (load C). Blood samples were drawn at 0, 15, 30, 60, 90, 180, 240, and 300 min. Urine specimens were collected during the time intervals -2 to 0, 0-2, 2-4, 4-6, and 6-24 h. RESULTS: Pharmacokinetic parameters of strontium bioavailability were comparable for all 3 loads. In detail, fractional absorption at 240 min for loads A, B, and C was 12.1 +/- 0.7%, 13.0 +/- 1.1%, and 12.2 +/- 0.7%, respectively. Areas under the curve for 0-240 min were 70.8 +/- 6.3, 69.6 +/- 3.5, and 65.8 +/- 5.1 micromol*h/L for loads A, B, and C, respectively (NS). Moreover, fractional strontium excretion values of 5.1 +/- 0.8% (load A), 5.8 +/- 0.4% (load B), and 5.2 +/- 0.8% (load C) were not significantly different. CONCLUSIONS: Lactose does not have a beneficial effect on calcium bioavailability in lactose-tolerant adults.

Removal of strontium by the chelating agent acetylamino propylidene diphosphonic acid in rats.

Studies of the effects of the chelating agent, calcium acetylamino propylidene diphosphonic acid (Ca-APDA), on the removal of radioactive strontium with two administration modalities were carried out in rats. The parenteral (intraperitoneal) administration of 150, 300, or 600 mg kg(-1) Ca-APDA was carried out for 3 d, 10 min after exposure of the animals to the strontium injection. On the first day post-treatment, the retention of strontium in the whole body decreased to 90.1%, 83.9%, and 35.1% that of the control level, respectively. The strontium deposited in femur of 600 mg kg(-1) Ca-APDA group was lowered to 28.4% of the control value. A single oral dose of 600 mg kg(-1) Ca-APDA administered simultaneously with, or 10 min after, oral administration of strontium, radionuclide retention in the whole body was reduced after 1 d to 42.9% and 31.9% of the control, respectively; meanwhile the strontium deposited in the femur was reduced to 16.9% and 29.3% of the control. In conclusion, the results indicate the efficacy of the new agent, Ca-APDA, to remove radioactive strontium from the body, or to inhibit the strontium intestinal absorption, in radio-strontium contaminated individuals.

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion.

Strontium metabolism has attracted considerable interest because of to its interaction with calcium, the bone alterations detected after treatment with strontium, and its potential value as a paleodietary indicator. The effects of ethanol on strontium and barium metabolism-another divalent cation which also accumulates in bone--is largely unknown. Based on this fact, we have determined bone content and fecal and urinary excretion of Ba and Sr in four groups of eight animals each pair-fed for 8 wk with (1) a nutritionally adequate diet, (2) a 36% (as energy) ethanol-containing isocaloric diet, (3) a 2% protein, isocaloric diet, and (4) a 36% ethanol, 2% protein isocaloric diet, following the Lieber-DeCarli model. Five additional rats were fed with the control diet ad libitum. We have found that ethanol tends to decrease and a low protein diet to increase bone strontium content; the decrease in bone strontium in the ethanol-fed rats is accompanied by an increase in the absolute excretion of strontium in urine. Ethanol also decreases bone barium content, but the effect of ethanol on urinary barium excretion is opposite that of strontium, a decrease. Thus, we conclude that ethanol alters both barium and strontium metabolism and bone deposition.

Calcium and strontium metabolic studies in patients on CAPD.

BACKGROUND: Strontium is known to affect calcium metabolism both experimentally and in clinical studies on conditions other than end-stage renal failure (ESRF) and continuous ambulatory peritoneal dialysis (CAPD). OBJECTIVE: To investigate Sr metabolism in relation to that of Ca in ESRF patients undergoing CAPD, and the possible influence of the duration of treatment. DESIGN: Cross-sectional observational study. SETTING: University medical center and Institute of Nuclear Physics. PATIENTS: Twenty-four patients on CAPD; 14 chronic renal failure (CRF) patients not on dialysis, and 52 healthy controls. MEASUREMENTS: Calcium and Sr content of serum, urine or dialysate effluent, and selected dietary products. RESULTS: Calcium and Sr are absorbed by the intestinal tract of healthy subjects with equal efficiency. Serum Ca levels were considerably lower in CRF patients than in healthy subjects and patients on CAPD (p < 0.001). Serum Sr was significantly higher in both CAPD and CRF patients than in healthy controls (p < 0.001). The Sr/Ca ratio in the sera of the healthy subjects was defined by the preferential excretion of Sr over Ca by the kidney. This preferential excretion was lost during renal failure. During treatment there was a tendency for the uptake of both Ca and Sr to increase. CONCLUSIONS: Strontium is accumulated in the body during renal failure and CAPD cannot restore normal levels. Considering the varying effects of different doses of Sr on bone metabolism experimentally, it would be interesting to determine by further studies the possible significance of the observed Sr accumulation for renal bone disease.