HDL biology
The first molecular characterization of avian CETP finds chicken CETP activity rises with dietary cholesterol and falls with egg-laying maturity, likely regulated by estrogen (Comp Biochem Physiol B 2007)
Original title: Molecular characterization and expression of the cholesteryl ester transfer protein gene in chickens
Cholesteryl ester transfer protein (CETP) cDNA was isolated from chicken liver, and recombinant protein overexpressed in HEK293 cells showed cholesteryl ester transfer activity in both media and cell lysates. Northern blot analysis detected chicken CETP mRNA in liver, brain, heart, and spleen, and both CETP mRNA and plasma CETP activity increased with dietary cholesterol supplementation, similar to humans. Hepatic CETP mRNA and plasma CETP activity were significantly lower in mature, egg-laying hens than in immature female chickens, but unaffected by age in males, and estradiol administration to males produced changes similar to those seen in females. This is the first report of the molecular characterization of an avian CETP, suggesting estrogen-regulated CETP impairment plays a role in egg production in laying hens.
Original abstract
The cDNA for cholesteryl ester transfer protein (CETP), a protein that catalyzes cholesteryl ester transfer between very low density and high density lipoproteins in plasma, was isolated from chicken liver. When the recombinant protein was overexpressed in HEK293 cells, cholesteryl ester transfer activity was observed in media and cell lysates. By Northern blot analysis, chicken CETP mRNA expression was detected in liver, brain, heart, and spleen. Changes in chicken CETP mRNA expression and plasma CETP activity with nutritional state were examined and found to increase following dietary supplementation with cholesterol in a similar way as in humans. Both the hepatic CETP mRNA levels and plasma CETP activity were significantly lower in mature (i.e egg-laying) hens than in immature female chickens, but were unaffected by age in male animals. Similar changes to those observed in female chickens were observed upon estradiol administration of males. The present study is the first to report the molecular characterization of an avian CETP, and the impairments of CETP gene and activity, which might be regulated by estrogen, play an important role in egg production in laying hens, demonstrating species-specific differences in the lipid metabolism of avian and mammalian species.
Summary written by cetpinhibition.org from the published abstract; figures as published. Page updated 19 August 2026. Methods.