Modification of bile acid profiles in rat intestine after irradiation: Alteration of both intestinal reabsorption and hepatic secretion three days after exposure
P. Scanff, S. Grison, N.M. Griffiths
XVII International Bile-Acid Meeting, Freiburg (Germany), 2002, may 30-june 1.
In the days following accidental or therapeutic exposure to high dose of ionising radiation, gastrointestinal injuries may ensure. Radiation induced damage to small intestinal mucosa is probably aggravated by qualitative and quantitative changes in the bile acid pool reaching the gut. However, intestinal bile acid malabsorption, classically evoked in these changes, may also be associated with altered hepatic bile acid biosynthesis.
Thus, these two major steps of the enterohepatic recycling of bile acids were explored in the rat, 3 days after exposure to 8 Gy total body gamma 60Co irradiation. Using the technique of wash-out associated with HPLC analysis, the enterohepatic recycling of the major individual bile acids was studied in controls (sham irradiated) and irradiated rats.
Wash-out of bile for 24 hours in the two groups showed that intestinal reabsorption of total bile acids was not significantly modified after exposure to ionising radiation but reabsorption of btauromuricholate (TMC) and taurocholate (TC) was decreased whereas it was increased for taurochenodeoxycholate (TCDC) and taurocholate (TDC). Concomitantly, hepatic synthesis of TC and glycocholate (GC) was enhanced but remained unchanged for betaTMC and TCDC. These results are consistent with the observed changes of bile acid profiles in bile.
Thus, radiation induced changes of the pool of bile acid reaching the intestine is not only due to expected intestinal malabsorption but also to changed hepatic bile acid synthesis. Moreover, these two steps are modified differently for each bile acid.