Biliary excretion of dolichols and β‐hexosaminidase—Effect of ethanol and glucagon

Abstract

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.

Accumulation of Dolichol in Older Tissues Satisfies the Proposed Criteria To Be Qualified a Biomarker of Aging

“…Shrinkage of tissue because of increased lysosomal degradation in the process of atrophy does not affect the dolichol content and concentration increases (13). Small quantities of dolichol that may be excreted into the urine at least in part is derived from the lysosomes of the excretory organ (14), and serum dolichol levels may be elevated in chronic cholestatic liver diseases (15). Recent evidence shows that phagocytosis may cause the degradation and disposal of the engulfed dolichol (13), possibly because of nonenzymatic free radical-mediated decomposition (16).…”

Whey Protein Concentrate WPC-80 Intensifies Glycoconjugate Catabolism and Induces Oxidative Stress in the Liver of Rats

“…Thus, changes in exoglycosidases activity may indicate catabolism and degree of remodelling of tissues/extracellular matrix [ 9 ]. Increased activity of exoglycosidases was recorded in the course of metabolic diseases [ 31 ], autoimmune diseases [ 32 ], cancer [ 33 ] and liver diseases [ 34 , 35 , 36 ]. The activity of exoglycosidases may be modified by environmental factors, diet and lifestyle [ 9 ].…”

“…It is well known that hepatic glycoconjugates include structural, transport and secretory proteins, as well as tissue compatibility (histocompatibility) antigens encoded by MHC genes. The oligosaccharide chains of hepatic glycoproteins are also found on the outer surface of cell membrane, which participate in signal transduction and immune response pathways, while the glycoprotein transporters are involved in the transport of bile acids, glucose and growth factors [ 34 , 35 , 36 , 38 ]. It is suggested that increased catabolism of hepatic glycoconjugates may affect the cell structure and organisation of the liver tissue [ 39 ].…”

“…It appears that raised activity of lysosomal hydrolases may indicate intensified liver metabolic processes and also impairment of liver function as a result of WPC-80 supplementation. Increased activity of exoglycosidases has been reported in numerous liver diseases, such as: primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH), non-alcoholic fatty liver disease (NAFLD) and hepatic cholestasis [ 34 , 35 , 36 , 38 ]. It has been demonstrated that in inflammatory conditions lysosomal exoglycosidases are released from the liver into the blood, where they are caught by specific receptors located on the surface of macrophages [ 39 ].…”