Differences in the Renal Handling of Pancreatic and Salivary
Amylase in the Rat

Mályusz, M.; Wrigge, P.; Caliebe, D.; Das, Jyotirmoy

doi:10.1159/000468719

Cited by 4 publications

(1 citation statement)

References 13 publications

(19 reference statements)

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“…Amylase reabsorption is relatively low: 50% on the aver age [25]. Studies in rats [26] and humans [27,28] have indicated that the FR of both isoenzymes may be differ ent. No data are available on the influence of tubular reab sorption on the IgG and amylase clearance ratios.…”

Section: Introductionmentioning

confidence: 99%

Clearance Ratios of Amylase Isoenzymes and IgG Subclasses: Do They Reflect Glomerular Charge Selectivity?

Buis¹,

Wever²,

Koomen³

et al. 1997

Nephron

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The clearance ratios of endogenous plasma proteins with the same size but a different charge, such as the amylase isoenzymes and the immunoglobulin (Ig) G subclasses, have been used to assess glomerular charge selectivity in man. These proteins are, however, subject to tubular reabsorption. In this study we measured the IgG subclass/IgG clearance ratios for IgG1 (pi 8.0-9.5), IgG2 (pI 7.0-7.5) and IgG4 (pI < 6) in 6 healthy volunteers. Our results suggested a selective influence of tubular reabsorption: the IgG1/IgG clearance ratio was 0.68 ± 0.14 (mean ± SD) and lower than IgG2/IgG (2.02 ± 1.06, p ≤ 0.01). IgG4/IgG was 0.89 ± 0.39. In addition, we studied the clearance ratios of pancreatic (PA, pI 7.0) and salivary amylase (SA, pI 5.9-6.4) and of IgGl and IgG2 in 8 patients with minimal change nephrotic syndrome (MCNS), 11 patients recovering from acute tubular necrosis (ATN) and 9 healthy volunteers (controls). In MCNS glomerular charge selectivity is lost, while in recovering ATN tubular function is severely disturbed. The PA/SA clearance ratio was 3.25 ± 0.89 in controls, reflecting intact glomerular charge selectivity. In MCNS patients the PA/SA clearance ratio had decreased to 1.21 ± 0.23 (p ≤ 0.001). In ATN patients the PA/SA clearance ratio was reduced as well: 1.55 ± 0.41 (p < 0.001), although the aselective nature of the proteinuria and the modest albuminuria indicated intact glomerular charge selectivity. The IgGl/ IgG2 clearance ratio was 0.54 ± 0.15 in controls, again suggesting preferential tubular reabsorption of IgGl. In MCNS patients the IgG1/IgG2 clearance ratio was 0.16 ± 0.10 (p ≤ 0.001); this probably reflects the relatively increased glomerular sieving of IgG2 when glomerular charge selectivity is lost. In ATN patients the IgGl/IgG2 clearance ratio was 1.07 ± 0.47 (p ≤ 0.001), which suggests a partial loss of preferential reabsorption of IgGl. It was concluded that the PA/SA clearance ratio is influenced by loss of tubular function and therefore does not reflect glomerular charge selectivity specifically. The IgG1/IgG2 ratio cannot be used to assess glomerular charge selectivity either because of the interference of selective tubular reabsorption of the subclasses. These findings put the assessment of glomerular charge using endogenous proteins in a new light and bring forward the necessity to interpret these ratios with the outmost cautiousness.

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Section: Introductionmentioning

confidence: 99%