Strenuous physical activity, aspirin and heat stress increase urinary dolichols: evidence for lysosomal origin of urinary dolichols

Beta-N-acetylhexosaminidase activity and isoenzyme profile in the kidney and urine of trained rats

Lysosomes play an important role in the immune system functioning and are involved in different aspects of inflammatory reaction, repair processes and tissue damage at various levels. Among various effects, it is known that physical exercise influences the release of different lysosomal components. The aim of this study was to evaluate enzyme activity and isoenzymatic profile of beta-N-acetylhexosaminidase both in kidney and urine of normal and trained rats. Enzyme activity was measured by fluorimetric assay while beta-N-acetylhexosaminidase isoenzymes were separated using DEAE-cellulose chromatography. Hexosaminidase specific activity was significantly increased in urine of trained rats whereas there was no increase in the kidneys of trained rats. Indeed, no significant differences were observed in the isoenzyme profile of kidney and urine extracts from normal and trained rats. Our findings suggest the exercise-induced release of lysosomal enzymes is a functional effect and not due to disruption of lysosomal membranes.

Biliary excretion of dolichols and beta-hexosaminidase--effect of ethanol and glucagon

Alcohol has been reported to increase the urinary excretion of dolichols, and urinary dolichols are suggested to be derived from the lysosomes of the renal cells. In the present study we examined the effects of alcohol and glucagon on the biliary excretion of dolichols in rats. Chronic ethanol treatment decreased both biliary dolichol and beta-hexosaminidase excretion. The absolute amount of dolichol excreted into the bile correlated highly significantly with the absolute amount of biliary beta-hexosaminidase. Our results indicate that biliary dolichols are--at least in part--derived from hepatic lysosomes. Decreased biliary dolichol output during chronic alcohol administration suggests that urinary and biliary dolichol excretions are regulated independently of each other.