[Effect of a long-term cholesterol-rich diet on the serum and hepatic lipid and lipoprotein levels in normotensive and spontaneously hypertensive rats].

There are great species and individual differences in response of the organism to a diet, rich in cholesterol. In the present study the author used two types of rats-normotonic of Wistar strain and spontaneously hypertonic of Okamoto--Aoki strain. The animals were fed with a diet of O'Neil, rich in cholesterol, for various periods of time. The levels of liver lipids and serum lipoproteins were raised only in the normotonic Wistar rats at early periods (4 months). The levels of serum lipids were elevated only after 10- and 11-month feeding with a diet, rich in cholesterol. She discusses the possibility that the increased exogenic transport of cholesterol and lipids could be compensated by enhanced metabolism in the peripheral tissues and by suppression and catabolism of cholesterol in liver at earlier stages. She suggests that the early elevation of lipoproteins could be due to "intermediary" lipoproteins, rich in cholesterol. This is proven also by the disc electrophoresis of serum lipoproteins, revealing intensification of alpha-lipoprotein fraction and the intermediary fraction between beta-lipoproteins and pre-beta-lipoproteins. There is no humoral syndrome, observed in the normotonic Wistar rats, in the spontaneously hypertonic rats, which have a--6-month diet, although the levels of liver lipids are raised significantly, when they are compared with the control group. She discusses the possibility for greater centrifugal transport of this kind, since more cholesterol and lipoproteins are measured in the vascular wall than in the normotonic animals.