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Exposure related observations in humans: other data

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Administrative data

Endpoint:
exposure-related observations in humans: other data
Type of information:
experimental study
Adequacy of study:
key study
Study period:
No data
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2000
Report date:
2000
Reference Type:
publication
Title:
The effect of pregnancy on renal clearance of boron in humans: A study based on normal dietary intake of boron.
Author:
Pahl MV, Culver BD, Strong PL, Murray FJ & Vaziri ND
Year:
2001
Bibliographic source:
Toxicological Sciences 60: 252 - 256.

Materials and methods

Type of study / information:
In vivo human excretion of boron, specifically examining renal clearance.
Endpoint addressed:
basic toxicokinetics
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Boron intake was from the background in the diet. In 16 second-trimester women and 15 non-pregnant age-matched referents, dietary boron provided the blood and urine boron concentrations used for calculating boron clearance. Blood for boron, creatinine and urea was collected at the start, at two h and 24 h. Urine was collected during the first two hours in the Clinical Research Centre and during 22 h outside the centre for measurement of volume, boron and creatinine. Renal boron clearance measured over the initial 2 h, the most complete urine collection period since after that time the accuracy of urine collection cannot be guaranteed. Differences in the serum creatinine clearances indicated that urine collection had not been complete over the entire 24 h collection period.
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Boron
EC Number:
231-151-2
EC Name:
Boron
Cas Number:
7440-42-8
Molecular formula:
B
IUPAC Name:
boron
Details on test material:
- Name of test material: Boron

Method

Ethical approval:
not specified
Details on study design:
Boron intake was from the background in the diet. In 16 second-trimester women and 15 non-pregnant age-matched referents, dietary boron provided the blood and urine boron concentrations used for calculating boron clearance. Blood for boron, creatinine and urea was collected at the start, at 2 h and 24 h. Urine was collected during the first 2 h in the Clinical Research Centre and during 22 h outside the centre for measurement of volume, boron and creatinine. Renal boron clearance measured over the initial two h, the most complete urine collection period since after that time the accuracy of urine collection cannot be guaranteed. Differences in the serum creatinine clearances indicated that urine collection had not been complete over the entire 24 h collection period.
Exposure assessment:
not specified

Results and discussion

Results:
The pregnant and non-pregnant boron intake was 1.35 mg boron/24 h and 1.31 mg boron/24 h respectively. Renal boron clearance measured over the initial 2 h, the most complete urine collection period, was 68.30 ± 35.0 mL/min/1.73 m2 for pregnant subjects and 54.31 ± 19.35 mL/min/1.73 m2 for non-pregnant subjects based on surface area. Based on body weights, the renal clearances were 1.02 ± 0.55 mL/min/kg and 0.8 ± 0.31 mL/min/kg for pregnant and non-pregnant subjects respectively. For the 24 h period, where urine collection was known not to be complete, the renal clearance was 61.04 ± 36.7 mL/min/1.73 m2 for pregnant subjects and 43.85 ± 21.59 mL/min/1.73 m2 for non-pregnant subjects based on surface area. Based on body weights, the renal clearances were 0.92 ± 0.59 mL/min/kg and 0.64 ± 0.4 mL/min/kg for pregnant and non-pregnant subjects respectively. The baseline plasma levels of boron were 0.022 ± 0.013 and 0.023 ± 0.015 mg B/mL for non-pregnant and pregnant subjects respectively. At 2 hour and 24 hours the levels were as follows: 2 hours: 0.024 ± 0.015 and 0.018 ± 0.011 mg B/mL for non-pregnant and pregnant subjects respectively; 24 hours: 0.027 ± 0.018 and 0.013 ± 0.006 mg B/mL for non-pregnant and pregnant subjects respectively. Comparison of renal boron clearance with creatinine clearance indicated that tubular reabsorption of boron occurred in both pregnant and non-pregnant women.

Applicant's summary and conclusion

Conclusions:
Comparison of renal boron clearance with creatinine clearance indicated that tubular reabsorption of boron occurred in both pregnant and non-pregnant women.