Journal of Lipid Research, Vol 34, 807-814, Copyright © 1993 by Lipid Research, Inc.
Hepatic production of very low density lipoprotein, catabolism of low density lipoprotein, biliary lipid secretion, and bile salt synthesis in rats fed a bean (Phaseolus vulgaris) diet
MP Marzolo, L Amigo and F Nervi
Departamento de Gastroenterologia, Facultad de Medicina, Pontificia Universidad Catolica de Chile, Santiago.
Rats fed a bean diet develop a significant hypocholesterolemia. The
catabolism of low density lipoprotein (LDL; d 1.019-1.063 g/ml) was studied
in vivo and in vitro in the isolated perfused liver of rats fed either a
casein or a bean diet. The clearance of LDL was significantly increased by
100% from 0.38 +/- 0.04 to 0.63 +/- 0.04 ml/h x 100 g body wt in vivo in
the bean-fed rat. Similarly, the clearance of homologous and heterologous
(human) LDL was also increased by 100% in the isolated perfused liver of
bean-fed animals. Spleen, kidney, and hepatic cholesterogenesis was
increased by 150% in these animals. Bile salt synthesis was increased from
1.54 +/- 0.02 to 2.84 +/- 0.09 nmol/min x g liver wt (P < 0.02) and
biliary cholesterol output by 200% from 0.81 +/- 0.03 to 2.18 +/- 0.04
nmol/min x g (P < 0.02) in the isolated perfused liver of rats fed a
bean diet. These results explained the depletion of hepatic cholesterol and
were consistent with the LDL turnover studies, suggesting that apoB/E
receptor activity was increased in these animals. ApoB and triglyceride
secretion in the d < 1.060 g/ml lipoprotein fraction of liver perfusates
remained normal in the bean-fed rats. In contrast, total sinusoidal
cholesterol output isolated in the d < 1.060 g/ml fraction significantly
decreased by 100% after 90 min of perfusion. Cholesterol output in the d
> 1.060 g/ml lipoprotein fraction was unmodified by the bean diet. These
data demonstrate that key metabolic pathways of hepatic cholesterol are
modified in the bean-fed rat.(ABSTRACT TRUNCATED AT 250 WORDS)