Kidney Ageing and Renal Excretion of Amylase

Brohée, Dany; Rondelez, Ludovic; Bain, H H; Maertelaer, Viviane De

doi:10.1159/000212561

Cited by 2 publications

(1 citation statement)

References 13 publications

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“…2 The enhancement of the amylase to creatinine clearance ratio found in the elderly may mainly reflect modifications in glomerular filtration dynamics. 7 The single most important physiologic abnormality in the aging kidney is the decline in glomerular filtration rate. s However, why levels of both P-and S-type isoamylases are higher in women in the third and fourth decade than they are in men, and why isoamylase levels tend to be increased in younger age groups, is still obscure.…”

Section: Discussionmentioning

confidence: 99%

Age and sex-dependent alterations of serum amylase and isoamylase levels in normal human adults

et al. 1994

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Total amylase and salivary- and pancreatic-type isoamylase levels were assayed in sera from 606 apparently healthy adults of different sex and age groups. There were significant differences in both total amylase and isoamylase levels, depending on age and sex, one of the characteristics being that levels of these three enzymes were significantly higher in the elderly group in both men and women than in other age groups. Another feature was that all of these enzyme levels were significantly greater in women in the third and fourth decade than in men. Age and sex differences should be taken into consideration in the evaluation of mild hyperamylasemia.

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Section: Discussionmentioning

confidence: 99%

Age and sex-dependent alterations of serum amylase and isoamylase levels in normal human adults

et al. 1994

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Renal Disposition of Amylase, Lipase, and Lysozyme in the Dog

Jacobs

1988

Vet Pathol

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Abstract. Normal adult dogs were given intravenously lysine hydrochloride to abolish renal tubular reabsorption. The treatment caused tubular proteinuria. Once forced diuresis was established, fractional clearances for amylase, lipase, and lysozyme increased five-, 18-, and 857-fold over the baseline values, respectively. There was relatively little tubular reabsorption of amylase, and urinary amylase activity remained low. A renal arteriovenous difference in amylase activity was not present. Urinary amylase activity could not be reactivated by the addition of serum or treatment with dithiothreitol. Urinary inhibitors of amylase activity were not detected. Immunoreactive urinary amylase did not exceed kinetically measured urinary amylase. Therefore, the presence of irreversibly inactivated amylase did not explain the low fractional clearance of amylase. A small amount of serum macroamylase was present, but macroamylasemia did not account for canine amylase failing to pass the glomerular filter. It appears that the renal loss of amylase in the dog is not an important excretory route.Canine a-amylase has a molecular weight of 54 kilod a l t o n~,~ which is similar to human a-amylase.8 In both species, the kidney is believed to be an important excretory route for amylase.11,28 In man, the measurement of urinary amylase activity and amylase clearance in relation to creatinine can have diagnostic importance.I5 The renal clearance rate of amylase in the dog is reported to be similar to the rate in man." Dogs have greater than twice the serum amylase activity compared with man, yet they have normally little or undetectable urinary amylase activity. Even with greatly increased serum amylase activity resulting from experimentally induced pancreatitis or infusion of supernates of pancreatic homogenates, the urinary loss of amylase appears minimal in d o g~.~,~,~J~,~~ It has been hypothesized that canine amylase is inactivated in the glomerular filtrate by unknown mechanisms or is reabsorbed by tubular epithelial cells.L1 Metabolic inhibitors of canine renal tubular epithelial cells increased the amylase to creatinine clearance ratio, suggesting that tubular cells normally reabsorbed amylase activity; however, the influence on the ratio of decreased creatinine secretion by the metabolically inhibited tubular epithelial cells was not ~0nsidered.I~ The low concentrations of urinary calcium and protein may cause urinary amylase activity to be lower than anticipated, since both are needed for optimal activity,12,23 although urinary amylase activity does not appear to be inhibited in man in such a manner. Changes to essential sulfhydryl groups in the amylase molecule also may result in enzyme inactivation, as reported for human amy1a~e.I~ It is possible that canine urine may contain inhibitors of amylase activity, but early data based on a saccharogenic technique for measuring amylase activity do not support this hypothesis.15 In man, approximately 45% of filtered amylaseZ8 and almost all lipase19 are reabsorbed by renal tubula...

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Kidney Ageing and Renal Excretion of Amylase

Cited by 2 publications

References 13 publications

Age and sex-dependent alterations of serum amylase and isoamylase levels in normal human adults

Age and sex-dependent alterations of serum amylase and isoamylase levels in normal human adults

Renal Disposition of Amylase, Lipase, and Lysozyme in the Dog

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