1. 4th Department of Internal Medicine, 1st Faculty of Medicine and General University Hospital, Charles University, 128 08 Prague, Czech Republic
2. Institute of Medical Biochemistry and Laboratory Diagnostics, 1st Faculty of Medicine and General University Hospital, Charles University, 128 08 Prague, Czech Republic
3. Department of Physiology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic
4. Institute of Physiology, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic