Fall in the Inulin Clearance Following a Single Injection

Barnard, H. F.; Bassir, O.; Hough, J.M.

doi:10.1113/expphysiol.1955.sp001118

Cited by 8 publications

(4 citation statements)

References 4 publications

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“…This has also been demonstrated by paper electrophoresis and by differential precipitation with ethanol (Bassir 1956). The continuous fall in inulin clearance after a single intravenous injection in man may also be explained by inhomogeneity, high molecular weight fractions supposedly being excreted slower than the low molecular weight fractions (Ferguson et al 1950, Barnard, Bassir andHough 1955). (Drew and Haworth 1928).…”

Section: Discussionmentioning

confidence: 99%

Renal Clearances of Inulin, Polyfructosan‐S and a Polyethylene Glycol (PEG 1,000) in the Rat

Berglund

1965

Acta Physiologica Scandinavica

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Berglund, F. Renal clearance of inulin, polyfructosan‐S and a polyethylene glycol (PEG 1,000) in the rat. Acta physiol. scand. 1965. 64. 238–244. The renal clearances of inulin, polyfructosan‐S and PEG 1,000 were measured in the rat by means of a constant infusion technique. The inulin/PEG 1,000 clearance ratio in 10 rats averaged 0.81, and polyfructosan‐S/PEG 1,000 ratio in 10 rats averaged 0.87. The clearance ratios differed signicantly from unity and were not influenced by phlorizin. The restricted filterabliity of the two polysaccharides in the rat is attributed to the pore size of the glomerular membrane, and a relationship between pore size and animal size is suggested.

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Section: Discussionmentioning

confidence: 99%

Renal Clearances of Inulin, Polyfructosan‐S and a Polyethylene Glycol (PEG 1,000) in the Rat

Berglund

1965

Acta Physiologica Scandinavica

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“…Intravenous injection of an analyte yields an essentially instantaneous increase followed by a decline in s A , thereby eliminating any possibility of ambiguity about ds A /dt. One example of this involves the injection of inulin [122,140,141] which is a non-metabolisable oligosaccharide [142]. The data of Ferguson and colleagues show that both the serum inulin concentration (s In ) and the inulin excretion rate (J In ) decline approximately exponentially after injection.…”

Section: Decreasing S a (Ds A /Dt < 0)mentioning

confidence: 99%

Expressing the quantity of urinary analytes: a discussion of some issues arising from the monitoring of the menstrual cycle

2020

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Practical domestic monitoring of the menstrual cycle requires measurements of urinary metabolites of reproductive hormones: oestrone glucuronide (E1G) and pregnanediol glucuronide (PdG). Data reported in the literature are expressed as (i) concentration, without or with either creatinine- or specific gravity correction, or (ii) excretion rates. This variation in such a fundamental issue prompts consideration of the relationships between the four measures. Because the menstrual cycle kinetics of E1G and PdG are complex, we consider measurements of urinary creatinine, urea, galactose, xylose and inulin which tend to be more stable. We show that uncorrected concentration measurements of these urinary analytes can be positively correlated, negatively correlated or uncorrelated with the serum concentration. Based on measurements of urinary creatinine concentrations, urinary specific gravity and creatinine excretion rates, we conclude that urinary analyte concentration are likely to be more reliable when creatinine-corrected rather than corrected using specific gravity, but that both are less reliable than measurements of the excretion rate. This has implications for the quantitation of any urinary analyte, but especially for the monitoring of the menstrual cycle in which changes in E1G and PdG from one day to the next can be physiologically significant for a woman monitoring her fertility.

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“…Alternatively, a correlation of clearance with low flow rates may indicate a reabsorptive component in the handling of a filtrate by the renal tubular cells (Pitts, 1963). The possibility of inulin reabsorption has previously been considered (Ferguson, Olbrich, Robson & Stewart, 1950) although their results have been interpreted as being due to the heterogeneity of the inulin polymer (Barnard, Bassir & Hough, 1955).…”

mentioning

confidence: 99%

“…Harvey & Malvin (1965) (Pitts, 1963). The possibility of inulin reabsorption has previously been considered (Ferguson, Olbrich, Robson & Stewart, 1950) although their results have been interpreted as being due to the heterogeneity of the inulin polymer (Barnard, Bassir & Hough, 1955).…”

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confidence: 99%

Determination of the renal clearance of inulin in rats: lowered values at low urine flow rates

Barber

Bourne

1971

British J Pharmacology

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The renal clearance of inulin (ClIN) was measured in anaesthetized male rats using a continuous intravenous infusion method.ClIN was independent of urine flow rate provided this was greater than 003 ml/ minute.At flow rates lower than this, CIIN was reduced and appeared to correlate with the rate of flow.In experiments where a constant kidney function is required. e.g., pharmacokinetic studies, it is advisable to maintain urine, flow rates in the rat above-0-03 ml/minute.We are currently studying the distribution kinetics of neostigmine bromide in the rat. The clearance of inulin (CIIN) is monitored routinely in this work to assess renal function. For inulin, the clearance should be independent of plasma concentration and urine flow rate; Harvey & Malvin (1965) reported that in rats there is a lack of correlation between inulin clearance and flow rate. However, in the present distribution studies it was noted that at low rates of urine flow CIN was reduced and correlated with flow. These, results are reported here.Methods.-The method for the measurement of clearance was essentially that of Harvey & Malvin (1965). Male Wistar rats weighing 320-420 g were anesthetized by an intraperitoneal injection of ethyl carbamate (1-4 g/kg).The trachea, jugular vein, carotid artery and both ureters were cannulated with polyethylene tubing (Portex, PP50 In some experiments after measuring three control clearance periods neostigmine bromide C-14 was administered intravenously (10 jug/ 100 g or 20 ug/ 100 g body weight). In these experiments and also those of control groups the infusion rate was either 0-038 or 0075 ml/minute. In other experiments urine flow rate was altered by changing the infusion rate randomly in the range 0 009-0 075 ml/ minute. In these experiments arterial blood pressure (1 mmHg-=1333 mbar) was monitored from the carotid artery by means of a Condon manometer, arterial blood samples being obtained for assay from the femoral artery.The radioactive inulin was measured in plasma and urine samples using a Nuclear Chicago Unilux II liquid rcintillation spectrometer. Samples (0(05 ml) were assayed in a Triton X-100 scintillant (666-6 ml toluene, 333*3 ml Triton X-100 and 6 g butyl P.B.D. [2(4'-t-butyl phenyl)-5(4" biphenylyl)-1,3,4, oxadiazole]. All samples were corrected for quenching by the external standard ratios method.Results.-In control experiments, CIIN was measured at a constant infusion rate, mean urine flow was about 003 ml/min, CIIN was fairly constant and apparently independent of urine flow.In the first experiments in which neostigmine was administered the infusion rate of inulin was 0038 ml/minute. The CIIN fluctuated about the mean for any particular experiment, notably after the rapid intravenous ixljection of neostigmine. After neostigmine, the mean urine flow rate was only about 0015-0020 ml/min and the CGIN appeared to correlate with the flow rate. In later experiments infusion rate was raised to 0 075 ml/min to produce flow rates comparable to the controls. The C1IN was then fairly constant, ...

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Fall in the Inulin Clearance Following a Single Injection

Cited by 8 publications

References 4 publications

Renal Clearances of Inulin, Polyfructosan‐S and a Polyethylene Glycol (PEG 1,000) in the Rat

Renal Clearances of Inulin, Polyfructosan‐S and a Polyethylene Glycol (PEG 1,000) in the Rat

Expressing the quantity of urinary analytes: a discussion of some issues arising from the monitoring of the menstrual cycle

Determination of the renal clearance of inulin in rats: lowered values at low urine flow rates

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