AJP - Gastrointestinal and Liver Physiology, Vol 252, Issue 1 114-G119, Copyright © 1987 by American Physiological Society
Modulation of hepatic biotransformation and biliary excretion of bile acid by age and sinusoidal bile acid load
U. Baumgartner, K. Miyai and W. G. Hardison
Pericentral hepatocytes excrete bile acids more slowly and biotransform
them more than periportal cells. This may reflect adaptation to low
pericentral bile acid concentration or may be intrinsic. We studied two
models in which pericentral bile acid concentrations are high: the 72-h
choledocho-caval shunt (CCS) rat and the 3- to 4-wk-old rat. Livers were
perfused forward or backward to assess periportal or pericentral hepatocyte
function. Taurodeoxycholate (TDC) was infused at 32 nmol X min-1 X g
liver-1, and a bolus of [3H]TDC was given to assess metabolism and
excretion of bile acids. In CCS livers perfused backward, pericentral cells
resembled periportal cells of controls in that time to excrete 50% of
administered [3H]TDC (t50) was reduced by two-thirds and [3H]TDC
biotransformation was reduced by about half. In young livers t50 was half
that of adult livers when perfused backward. Biotransformation, however,
was not reduced. Young livers biotransformed more than adult controls for
any given residence time of bile acid in the liver. We conclude that the
difference between pericentral and periportal cells as regards bile acid
processing is adaptive. Livers from young rats biotransform more bile acid
than those from controls under similar conditions.
