Figure 2.

Copeptin levels in hypo-osmolal hypervolemia: the study subjects received 4 µg of desmopressin intravenously at 20:00 hours and at 08:00 hours on the following day. Simultaneously, they were instructed to drink 2 to 2.5 L of tap water during the night. Copeptin levels in hyperosmolal isovolemia: study subjects received 1 mL/kg/hour of 2% saline infusion from 20:00 hours to 08:00 hours, and 200 mL/hour of 5% saline infusion from 08:00 hours to 13:00 hours. They were instructed not to drink during the whole study period. The control experiment consisted of access to oral water ad libitum during the whole study period (modified from (22)). Boxplots indicate median and IQR and whiskers represent the range. Created with BioRender.com.