Coordinacy of lysosomal enzyme excretion in human urine.
AUTOR(ES)
Paigen, K
RESUMO
Assay conditions have been developed for the determination of urinary beta-glucuronidase, beta-galactosidase, alpha-galactosidase, and beta-hexosaminidase using fluorometric substrates. The assay conditions for beta-glucuronidase overcome interference by both low and high molecular weight inhibitors, a problem that has confused earlier studies of enzyme excretion. The four lysosomal enzymes are excreted corrdinately: although their absolute levels (in units per milligram of creatinine) vary during the day and from one day to the next, the ratio of one enzyme to another remains relatively constant. The lack of correlation betweem plasma and urine enzyme levels, together with the high molecular weights of these enzymes, suggests that the urinary enzymes are not derived by glomerular filtration. The lack of coordinacy with lactate dehydrogenase suggests they are not derived from exfoliated cells. by analogy with experimental animals, they may be derived from lysosomes extruded into the lumen of the proximal tubule by epithelial cells. There is considerable variation among a population of 125 healthy adult subjects for total enzyme excretion. Both total enzyme excretion and coordinacy ratios are log-normally distributed, suggesting that they are the resultants of many factors, each of which has a relative, or proportional, effect on enzyme excretion. About one-half the population variation resides in a process common to the excretion of all four enzymes (possibly the lysosome extrusion pathway), and about one-half resides in factors affecting each enzyme independently.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372590Documentos Relacionados
- Absorption of cumene through the respiratory tract and excretion of dimethylphenylcarbinol in urine.
- Thrombomodulin is present in human plasma and urine.
- Mycoplasmas in human pyelonephritis: demonstration of antibodies in serum and urine.
- Excretion of Trichloroethylene Metabolites in Human Urine
- Absorption of m-xylene vapours through the respiratory tract and excretion of m-methylhippuric acid in urine.