Pharmacologyonline 3: 617-624 (2006) Simonen et al. 617 SERUM SQUALENE AND NON-CHOLESTEROL STEROLS RELATED TO CHOLESTEROL SYNTHESIS AND ABSORPTION IN TYPE 2 DIABETES
Serum non-cholesterol sterols, cholestanol and plant sterols, campesterol and sitosterol, are known to positively reflect cholesterol absorption and negatively cholesterol synthesis. Opposite associations are obtained for cholesterol precursors, including squalene, cholestenol and lathosterol. We compared non-cholesterols and squalene in serum with those in lipoproteins, and related the values to absolute cholesterol synthesis and absorption percent of patients (n=33) with type II diabetes,
... e of body mass index (BMI) being 21-40.-Lipids in serum and ultracentrifuge fractions were measured with routine laboratory methods. Gas liquid chromatography was used to measure cholesterol, squalene and non-cholesterol sterols in serum and lipoproteins. Sterol balance technique was used to determine absolute cholesterol synthesis and a double label system for measurement of absorption percentage of dietary cholesterol-Two-thirds of the non-cholesterol sterols were carried in LDL and one-fifth in HDL, whereas squalene was mainly in VLDL and LDL. The synthesis and absorption markers were interrelated in serum and all lipoproteins suggesting intact regulation of cholesterol metabolism. The absorption and synthesis marker ratios to cholesterol were mostly similar in serum and lipoproteins, even though absorption sterols accumulated to HDL and IDL and synthesis markers in VLDL and IDL. The ratios to cholesterol of absorption markers were negatively, those of synthesis markers positively related to BMI in serum and most lipoprotein fractions, and also to respective absolute synthesis and absorption percentage of cholesterol. Also, the proportions of synthesis marker sterols to those of absorption markers (eg., lathosterol/sitosterol) were positively related to BMI and absolute synthesis and negatively to absorption percentage of cholesterol.-The findings indicate that even in patients with type II diabetes, including markedly increased body weight and altered cholesterol metabolism, measurement of serum non-cholesterol sterols and squalene reveals information of cholesterol synthesis and absorption without complicated clinical and laboratory methods.