Synthesis and absorption of cholesterol in Finnish boys by serum non-cholesterol sterols: the cardiovascular risk in Young Finns Study.
OBJECTIVE
Surrogate serum markers of cholesterol synthesis (e.g. squalene, lathosterol) and absorption (e.g. cholestanol, campesterol) were studied in adolescent boys to show whether homeostasis of cholesterol metabolism is maintained in different age cohorts and within different absorption levels.


METHODS
In random population samples of 12- (n=162), 15- (n=158), and 18- (n=148) year-old boys participating in Cardiovascular Risk in Young Finns Study serum sterols and squalene were measured with gas-liquid chromatography at baseline, and expressed as ratios to cholesterol. Quartiles of cholestanol indicating low to high cholesterol absorption were defined from whole population.


RESULTS
Age-dependent decrease of serum cholesterol was associated with increased synthesis and decreased absorption of cholesterol (e.g. campesterol 205+/-6 vs. 176+/-4 in 12- vs. 18-year-old, p<0.05). In whole population, synthesis and absorption markers were interrelated indicating maintenance of homeostasis of cholesterol metabolism. Synthesis markers decreased and those of absorption increased linearly from first (low absorption) to fourth cholestanol quartile (high absorption). Correlation between synthesis and absorption, however, was significant in the lowest quartile only (lathosterol vs. campesterol, quartile 1, r=-0.283, p<0.05; quartile 4, r=-0.070, NS).


CONCLUSIONS
Even though cholesterol absorption and synthesis are usually changed in opposite directions, in cases with high absorption the maintenance of homeostasis of cholesterol metabolism can be lost, so that synthesis and absorption of cholesterol are changed independently of each other.
Miettinen
Tatu A
TA
Department of Medicine, Division of Internal Medicine, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland. tatu.a.miettinen@helsinki.fi
Gylling
Helena
H
Viikari
Jorma
J
Lehtimäki
Terho
T
Raitakari
Olli T
OT
D000293:Adolescent; D000367:Age Factors; D015992:Body Mass Index; D002648:Child; D004083:Cholestanol / Q000097:blood; D002784:Cholesterol / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism*; D005387:Finland; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D010840:Phytosterols / Q000097:blood; D012885:Skinfold Thickness; D013185:Squalene / Q000097:blood
D010840:Phytosterols; C021273:campesterol; D013185:Squalene; C001521:lathosterol; D004083:Cholestanol; D002784:Cholesterol