Induction of cholesteryl ester transfer protein in adipose tissue and plasma of the fructose-fed hamster

Cholesteryl ester transfer protein (CETP) plays a pivotal role in the rever se transport of cholesterol and in the remodeling of circulating lipoprotei ns. While plasma and adipose tissue levels of CETP are affected by a variet y of metabolic conditions, the extent of the effects of dietary factors, ot her than high cholesterol feeding, are not well understood. To further expl ore this paradigm, male Golden Syrian hamsters were fed for 4 weeks with a 60%-enriched fructose diet (F) and were compared to a matched group of anim als fed with a normal chow diet (N). After feeding for 4 weeks, plasma insu lin concentrations were lower in animals fed fructose than in control anima ls (F: 3.3 +/- 0.8 vs N: 7.4 +/- 1.9 ng/mL; p<0.03), but there was no signi ficant difference in plasma glucose concentrations between the two groups ( F: 138 +/- 7 vs N: 148 +/- 10 mg/dL; p>0.05). Fructose-fed animals showed s ignificant increases in plasma triglyceride (F: 269 +/- 22 vs N: 165 +/- 22 mg/dL; p<0.01) and plasma cholesterol (F: 150 +/- 10 vs N: 113 +/- 6 mg/dL ; p<0.02) concentrations compared with control animals. Total CETP activity and immunoreactive mass were higher in the plasma of fructose-fed animals that in that of controls (F, 1036 +/- 70 vs N: 826 +/- 43 pmol/h/mL, p<0.04 and F: 24.5 +/- 3.1 vs N: 37.5 +/- 3.3 AU, p<0.02, respectively). Adipose tissue CETP mRNA levels, assessed by the very sensitive ribonuclease protec tion assay, were 53% higher in fructose-fed animals than in controls (F, 14 .1 +/- 2.0 vs N: 9.2 +/- 1.0 AU over a rRNA control; p<0.04). Adipose tissu e CETP activity and immunoreactive mass also showed a statistically signifi cant increase in the fructose-fed hamsters compared with those fed a normal diet (p<0.04). In conclusion, fructose feeding in Syrian hamsters induces a mixed dyslipid emia, These metabolic changes are accompanied by a significant increase in CETP levels, both in plasma and in adipose tissue. This phenomenon suggests that the increase in the expression of adipose tissue CETP may be caused e ither by the ambient hypercholesterolemia resulting from fructose feeding o r by an attenuation of a possible inhibitory effect of plasma insulin conce ntrations on the expression of adipose tissue CETP in this feeding paradigm . (C) 2001 Elsevier Science Inc. All rights reserved.