Cholesterol contents of various tissues of chickens with exogenous or endogenous hypercholesteremia

Cholesterol contents of 16 different tissues were determined in 12 normal roosters, 12 roosters with diet-induced, exogenous hypercholesteremia, 10 actively laying hens with minimal endogenous hypercholesteremia, and 12 nonlaying hens with hereditable extreme hyperlipidemia. The tissue cholesterol contents of the normal roosters were strikingly similar to that of the corresponding tissues of the mammals except for a low cholesterol content of the brain in chickens. The hypercholesteremia in the roosters fed a 2% cholesterol diet for 2 months was associated with an increase of cholesterol content in all tissues except the brain, muscle, and adipose tissue. The actively laying hens, on the other hand, had a decreased cholesterol content in most tissues, despite the persistence of a minimal hypercholesteremia for 18 months and significant aortic cholesterol accumulation with mild atherosclerosis. The nonlaying hens developed extreme hypercholesteremia and severe atherosclerosis but only a moderately expanded cholesterol pool in most tissues. The results indicated a remarkable difference in tissue response to diet-induced exogenous hypercholesteremia and endogenous hyperlipidemia associated with laying activity in chickens and the propensity of their aortas to accumulate excessive cholesterol in the presence of either endogenous or exogenous hyperlipidemia.