Previous studies revealed hepatic interactions of beta-carotene with alcohol in non-human
primates, but bile carotenoids and alpha-tocopherol have not previously been explored
in man.
To compare the plasma and biliary concentrations of carotenoids, retinoids and tocopherols
among controls and patients with biliary and pancreatic diseases, these compounds
were measured by high performance liquid chromatography in bile collected during 41
endoscopic retrograde cholangiopancreatographies.
In 14 subjects with normal endoscopic retrograde cholangiopancreatography (controls),
bile contained beta-carotene, alpha-carotene, lycopene, cryptoxanthin, lutein+zeaxanthin
(23.9 +/- 6.6, 3.9 +/- 1.1, 39.9 +/- 21.6, 22.5 +/- 4.6, 217.1 +/- 27.8 nmol/l, respectively)
with corresponding plasma values of 399.7 +/- 72.6, 88.5 +/- 18.8, 588.2 +/- 75.0,
145.1 +/- 25.9, 319.3 +/- 33.7 nmol/l. In 13 patients in whom bile duct stones impaired
biliary excretion (as reflected by raised serum bilirubin), beta-carotene was significantly
decreased in both plasma (199.6 +/- 35.5 nmol/l) and bile (9.4 +/- 2.0 nmol/l), with
a similar trend for other carotenoids. The beta-carotene plasma/bile ratio was maintained,
as well as a correlation between the two (r = 0.56; p = 0.048). Furthermore, in three
subjects with complete biliary obstruction, plasma beta-carotene (35.8 +/- 20.2 nmol/l)
decreased even more, probably reflecting malabsorption. In 11 patients with pancreatic
diseases, plasma and bile beta-carotene were 107.9 +/- 17.8 and 6.6 +/- 2.0 nmol/l
respectively, while a correlation between the two (r = 0.70; p = 0.018) again persisted,
confirming the role of plasma beta-carotene in determining bile concentrations. Indeed,
for the entire group (n = 41), the correlation between plasma and bile or red blood
cell beta-carotene was highly significant, whereas plasma/red blood cell ratios remained
unchanged. Similar findings were observed for alpha-tocopherol, with 8.4 +/- 0.9 mumol/l
in control bile (vs. 23.2 +/- 1.7 mumol/l in plasma), and no significant change in
the various groups.
1) Carotenoids and tocopherols undergo biliary excretion in man. 2) Biliary concentrations
reflect plasma levels in both normal and pathologic states. 3) Decreased biliary excretion
of carotenoids does not increase plasma concentrations.