In rats with experimental hypertension
the esterification of cholesterol and hydrolysis of
cholesterol esters in aortae, blood serum and liver
was investigated in vitro at atmospheric pressure and
at raised pressure of 200 Torr, i.e. a pressure similar
to that recorded in the arteries of hypertensive animals
in vivo. Hydrolysis of cholesterol esters was
enhanced in hypertensive animals. The increase
could be detected on incubation in vivo at atmospheric pressure and at 200 Torr in
serum and aortae, but in the liver only at atmospheric pressure. In hypertensive rats
no decline of hydrolysis in serum and aortae, which was associated with incubation
at 200 Torr in normotensive rats, was observed. Cholesterol esterification in serum
in vitro was greater at 200 Torr, while in aortae it declined. In hypertensive rats
esterification in serum was reduced, in aortae enhanced and in the liver the changes
were not significant. The results are discussed with regard to atherogenesis in
hypertension and with regard to enzyme adaptability.