Evaluation of the liver functional changes in modeling the hemodynamic effects of microgravity in bed rest studies

Abstract

Ultrasonic examinations of eight male volunteers during bed rest in the antiorthostatic position (ANOP) at–15° showed plethora in the venous system of the abdominal cavity and slow blood flow through the liver with no effect on biochemical parameters. The ¹³C-methcetine breath test (¹³C-MBT) with 100 mg of ¹³C-methoxymethacetine showed diminution of the metabolic capacity and decline in the rate of detoxification activity of the liver due to functional changes related to hemodynamic alterations in ANOP. ¹³C-MBT can be used as a noninvasive method for diagnosing functional changes in the liver induced by hemodynamic reorganization in microgravity and other states triggering similar hemodynamic mechanisms.