Journal of Lipid Research, Vol 22, 961-970, Copyright © 1981 by Lipid Research, Inc.
The biosynthesis, absorption, and origin of cholesterol and plant sterols in the Florida land crab
TS Douglass, WE Connor and DS Lin
In order to study the biosynthesis, composition, and origin of sterols in
the Florida land crabs, Cardisoma guanhumi (Latreille), we fed 17 male
crabs either a cholesterol-free or a high cholesterol diet for 2 to 7
weeks. The origin of sterols in these crabs, whether from biosynthesis or
from the diet, was determined by tahree procedures: the incorporation of
isotopic mevalonate into the cholesterol when the diet was
cholesterol-free; the absorption of isotopic cholesterol and sitosterol
from the diet; the cholesterol and plant sterol concentrations of
hepatopancreas, plasma, and muscle under conditions of cholesterol-free and
high cholesterol diets. In addition, the interconversion of cholesterol and
sitosterol was investigated. Dietary sterols of plant and animal sources
were readily absorbed and provided the major source of sterols for this
species of crab. The biosynthesis of cholesterol from mevalonate in this
crab was minimal. However, cholesterol was synthesized from dietary
sitosterol by dealkylation. Cholesterol and the three plant sterols (24
epsilon-methyl cholesterol, stigmasterol, and sitosterol) were found in the
hepatopancreas, plasma, and muscle of the crab. Plant sterols contributed
from 9 to 37% of the total sterols in the hepatopancreas, plasma, and
muscle of the crabs fed a cholesterol-free diet.