| Abstract: | The spectrum of bile acids and bile lipids in men exposed to 120-day head-down tilt was investigated. The test subjects were subdivided in to four groups: group 1-bed rest per se, group 2-bed rest + exercise, group 3-bed rest + drugs normalizing calcium metabolism, and group 4-bed rest + exercise + drugs. It was anticipated that biliary concrements would primarily be formed in group 1 and 2 subjects. They showed a low level of bile acids and a high content of total Ca and cholesterol in the bile, which was more pronounced in the C portion (decrease of the cholate/cholesterol coefficient). Group 2 subjects displayed a modified synthetic function of the liver: prevalence of tauroconjugates in the bile (decrease of the ratio of glucoconjugates to tauroconjugates). Group 3 and 4 subjects showed a faster synthesis of bile acids in the liver and a lower content of total calcium and cholesterol in the bile, the latter being more distinct in group 4 subjects. Positive dynamics of these parameters is a factor responsible for a reduced lithogeny of the bile. However, the test subjects of these groups exhibited hazardous changes that may be responsible for concrement formation. This is indicated by a lower concentration of the lipid complex in the bile, possibly at the expense of a lower content of phospholipids. This emphasizes the necessity of further search for prophylactic procedures aimed at normalizing the synthetic function of the liver under hypokinetic conditions. |
