Total lipids were extracted using chloroform/methanol
(2:1) as described by Folch et al. [11]. Five hundred-milligram
tissue/n ml serum was homogenized with chloroform/
methanol (2:1), filtered and washed with chloroform/methanol
at least three times. Calcium chloride, (0.02%), was added
to the mixture (20% of the total volume of the extract), mixed
vigorously and allowed to stand for a few minutes. The upper
layer was washed three times with 5-ml chloroform/methanol/calcium
chloride (3:48:48 v/v). The washed upper layer
was evaporated to dryness and the residue was redissolved in
a known volume of chloroform. From this, aliquots were used
for lipid analysis. Total cholesterol was estimated as described
by Abell et al. [12]. Triglycerides and phospholipids
were estimated by the method of Zilversmith and Davis and
Van Handel and Zilversmith respectively [