EXOGENOUS HYPERCHOLESTEROLEMIC RATS, COMPARED WITH THEIR PROGENITOR, SPRAGUE-DAWLEY RATS, PROMPTLY ALTER CHOLESTEROL-METABOLISM IN THE LIVER AND SECRETE CHOLESTEROL-RICH PARTICLES IN RESPONSE TO DIETARY-CHOLESTEROL
M. Sakono et al., EXOGENOUS HYPERCHOLESTEROLEMIC RATS, COMPARED WITH THEIR PROGENITOR, SPRAGUE-DAWLEY RATS, PROMPTLY ALTER CHOLESTEROL-METABOLISM IN THE LIVER AND SECRETE CHOLESTEROL-RICH PARTICLES IN RESPONSE TO DIETARY-CHOLESTEROL, Comparative biochemistry and physiology. B. Comparative biochemistry, 113(4), 1996, pp. 803-808
Early responses of cholesterol metabolism to dietary cholesterol were
compared between exogenous hypercholesterolemic (ExHC) and Sprague-Daw
ley rats. Both strains had a similar radioactivity of [C-14]cholestero
l in the serum half a day after the oral administration, but thereafte
r the radioactivity disappeared slowly in ExHC rats. ExHC rats promptl
y altered in response to the dietary cholesterol, activities of choles
terol 7 alpha-hydroxylase and cholesterol synthesis in the liver and f
ecal excretion of bile acids derived from [C-14]cholesterol administer
ed orally. Lymphatic transport for 24 hr of [C-14]cholesterol was simi
lar between the strains. Triton administration resulted in a marked ac
cumulation of cholesterol in serum d > 1.006 g/ml lipoproteins in ExHC
rats; in addition, the formation of cholesteryl esters from [C-14]ole
ic acid intravenously infused was greater in ExHC rats. These results
indicate that ExHC rats increase serum cholesterol in response to exog
enous cholesterol by decreasing the liver uptake and enhancing the sec
retion in the liver.