Hypercalcemia decreases bile flow and increases biliary calcium in the prairie dog.
BACKGROUND
Biliary calcium is known to play an important role in the pathogenesis of gallstones. Calcium salts are present in all pigment gallstones and are also present in the core of most, if not all, cholesterol gallstones.


METHODS
The effects of acute hypercalcemia on bile flow and biliary calcium secretion were examined in 22 prairie dogs during intravenous taurocholate infusion (0, 1.0, 2.25, and 4.5 mumol/kg/min).


RESULTS
Bile flow was linearly correlated with bile acid output in both control (y = 7.62x + 13.5, r = 0.98) and hypercalcemic (y = 7.00x + 10.4, r = 0.96) animals. At lower bile acid outputs (< 3.0 mumol/kg/min), biliary ionized calcium output per increment bile acid output was significantly increased in hypercalcemic animals (0.016 versus 0.011 mumol Ca++ mumol taurocholate, p < 0.001). Bile ionized calcium concentrations approximated Gibbs-Donnan predicted values only at low bile flow rate.


CONCLUSIONS
Hypercalcemia decreases bile flow and increases biliary ionized calcium concentration in the prairie dog. These effects favor the precipitation of calcium salts in bile.
Ahrendt
S A
SA
Department of Surgery, Johns Hopkins Medical Institutions, Baltimore, Md., USA.
Ahrendt
G M
GM
Pitt
H A
HA
Moore
E W
EW
Lillemoe
K D
KD
D000818:Animals; D001646:Bile / Q000378:metabolism*; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D006934:Hypercalcemia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D012016:Reference Values; D012044:Regression Analysis; D012589:Sciuridae
D002118:Calcium