Age-dependent enzymuria, proteinuria and changes in renal blood flow and glomerular filtration rate in rats
| Autor: | Carlos Piera, Josep Queralt, Gemma Casadevall, J. Setoain |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Aging
medicine.medical_specialty Urinary system Renal function Nephron urologic and male genital diseases Renal Circulation Iodine Radioisotopes Excretion chemistry.chemical_compound Internal medicine medicine Animals Rats Wistar reproductive and urinary physiology Kidney Creatinine Renal circulation urogenital system business.industry Iothalamic Acid Enzymes Rats Proteinuria medicine.anatomical_structure Endocrinology chemistry Renal blood flow Female Iodohippuric Acid business Glomerular Filtration Rate Developmental Biology |
| Zdroj: | Mechanisms of Ageing and Development. 82:51-60 |
| ISSN: | 0047-6374 |
| Popis: | The time course of urinary excretion of two enzymatic indicators of renal damage, N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP) was measured in female Wistar rats at different ages. NAG and AAP are localized at different sites of the nephron and are released into the urine when kidney damage occurs. Total protein flow, urinary volume and creatinine flow were also determined. In a parallel experiment, the effect of aging on renal blood flow (RBF) and glomerular filtration rate (GFR) was examined in young (1.5-month) adult (3-month) and elderly (20-month) female rats. Clearance following a single injection of [131I]o-iodohippurate (hippuran, OIH) was used for the measurement of effective RBF and as an index of tubular cell function. [125I]Iothalamate (IOT) clearance was used to measure GFR. With advancing age, an increase in NAG and AAP urinary flow appeared. The increases in protein excretion were greater than and previous to those of enzyme excretion. It is shown that absolute RBF and GFR (ml/min) in old rats are greater than in young or adult animals. When absolute RBF or GFR was divided by kidney weight (ml/min/g) no clearance changes appeared in any age group studied; only when clearance was expressed in relation to body weight (ml/min/100 g), a decrease in RBF and GFR was evidenced. This indicates that the rate of increase of both RBF and GFR with age is similar to that of kidney weight and lower than that of body weight. The present findings indicate that urinary markers of renal injury increase with age, whereas GFR and RBF only decrease when expressed as clearance related to body weight. |
| Databáze: | OpenAIRE |
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