Reagent for the enzymatic determination of serum total cholesterol with improved lipolytic efficiency.

Abstract

We describe a sensitive method for quantifying the extent of cholesterol ester cleavage during enzymatic assay of total cholesterol in serum. Lipids are extracted from the assay mixture with chloroform/methanol (1/1 by vol), concentrated, then quantified by "high-performance" thin-layer chromatography. Although with conventional enzymatic reagents for determination of serum total cholesterol the hydrolysis of the cholesterol esters may be incomplete, a new enzymatic cholesterol reagent (Monotest Cholesterol, High Performance, Boehringer Mannheim) gives virtually complete cholesterol ester cleavage (i.e., greater than or equal to 99.5%). Use of this reagent with its improved lipolytic efficiency yields results for serum total cholesterol that are identical to those measured with a candidate reference procedure involving alkaline cholesterol ester saponification.

Lower cortisol levels after oral glucose in subjects with insulin resistance and abdominal obesity

“…Total serum cholesterol was measured through the reaction of cholesterol esterase/cholesterol oxidase/peroxidase (Siedel et al, 1983) using a BM/Hitachi 747. VLDL-cholesterol was measured after ultracentrifugation at 45000 g. HDL cholesterol was quantified after precipitation with polyethylene glycol at room temperature (Kostner et al, 1985).…”

The effect of growth hormone replacement on serum lipids, lipoproteins, apolipoproteins and cholesterol precursors in adult growth hormone deficient patients

“…A fasting venous blood sample was taken into tubes containing sodium EDTA (1 g/l). Cholesterol and triglycerides were measured enzymatically (Siedel et al, 1983) and high density lipoprotein (HDL) cholesterol after precipitation of apolipoprotein B with dextran sulphate-manganese chloride. Low density lipoprotein (LDL) cholesterol was calculated by the Friedewald formula (LDL cholesterol = total cholesterol -0.45 triglyceride -HDL cholesterol in mmol/l) (Friedewald et al, 1972).…”

Species specificity in the blood cholesterol‐lowering effect of YM‐16638

“…In all animals studies, blood samples were obtained after 12 h overnight fasting before treatment (prevalue) (in rabbit and monkey studies) and at the end of the experimental period (in all animal experiments). Serum cholesterol, triglyceride, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were determined by enzymatic colorimetric methods (Allain et al, 1974;Siedel et al, 1981) (Boehringer Mannheim Mono-test cholesterol, TRIGLI-color, GOT-opt and GPT-opt, respectively, using a Hitachi 736-10 automatic analyser). HDL cholesterol in the supernatant after precipitation of LDL and VLDL cholesterol fractions was determined (Burnstein et al, 1970).…”