ABSTRACT
Cholesterol ester hydrolase (cholesterol esterase, EC 3.1.1.13) does not only act on cholesterol esters, but also on esters of fluorescein. Diesters as well as monoesters of this dye show neither color nor fluorescence, so that these compounds may be used as chromogenic or fluorogenic substrates. Splitting off the ester bonds immediately causes the return of the original properties of the fluorescein. Its dilaurate was found to be a specific substrate of cholesterol esterase, allowing the measurement of activities of this enzyme down to ranges of 0.01 U/1 by a fluorometric assay.
Subject(s)
Carboxylic Ester Hydrolases/metabolism , Pancreas/enzymology , Sterol Esterase/metabolism , Buffers , Cholesterol/metabolism , Humans , Hydrogen-Ion Concentration , Spectrometry, Fluorescence , Substrate Specificity , Surface-Active Agents/pharmacologyABSTRACT
Column chromatography of extracts and secretions of the pancreas as well as of sera from patients suffering from inflammations of this organ yields three esterases different from each other in molecular size. These enzymes could be shown to be not identical with lipase. They may be classified as aryl-esterases considering their activities in hydrolyzing synthetic substrates such as esters of fluoresceine with fatty acids. Fluoresceinedilaurate, therefore, proved to be very advantageous in an orally performed test of exocrine pancreatic function. Healthy persons show in this procedure relative excretion of fluoresceine during ten hours of 66.3 +/- 30.4%, patients suffering from pancreatic diseases only 12.7 +/- 9.8% of the dye.
Subject(s)
Esterases/metabolism , Fluoresceins , Pancreas/enzymology , Humans , Molecular Weight , Pancreatic Diseases/enzymologyABSTRACT
Exocrine insufficiency of the pancreas was identified by decreased splitting of the ester substrate and thus diminished excretion of fluorescein in the urine of persons with normal pancreatic function (test excretion). Unesterified fluorescein served to ascertain the standard excretion of fluorescein (= 100%). The relation of test excretion to standard excretion was expressed in %. Values of less than 20% in collected urine are pathologic. The range of 20-30% is questionable. Normal persons showed 30% or more. The method described is simple and without problems for the patient. The test was accurate in 93% of patients with a false negative in 1%. Practicability and results recommend the test as a screening method.
Subject(s)
Fluoresceins , Pancreatic Diseases/diagnosis , Administration, Oral , False Negative Reactions , Fluoresceins/administration & dosage , Fluoresceins/metabolism , Fluoresceins/urine , Humans , Laurates/metabolism , MethodsSubject(s)
Cholesterol/blood , Adult , Autoanalysis , Female , Humans , Male , Methods , Middle AgedABSTRACT
Post-heparin lipolytic-activity (PHLA) was studied in 10 healthy volunteers ingesting 0.5 g of ethanol/kg body weight initially and 0.1 g/kg body weight and hour over 5 hours. This dose led to enhancement in plasma triglycerides to about 170% of the pre-ethanol values. PHLA was determined before, 15 min, 1 and 5 hours after intake of the initial dose and showed no significant changes. These findings are compared with the results of earlier investigations. It is concluded that acute ethanol induced hyperlipoproteinemia in healthy man seems to be due mainly to enhanced hepatic synthesis of triglycerides and release of very low density lipoproteins and not to decrease catabolism of triglyceride rich lipoproteins.
