Release and decay kinetics of copeptin vs AVP in response to osmotic alterations in healthy volunteers
WK Fenske, I Schnyder, G Koch, C Walti… - The Journal of …, 2018 - academic.oup.com
The Journal of Clinical Endocrinology & Metabolism, 2018•academic.oup.com
Context Copeptin is the C-terminal fragment of the arginine vasopressin (AVP) prohormone
whose measurement is more robust than that of AVP. Similar release and clearance
characteristics have been suggested promoting copeptin as a surrogate marker. Objective
To characterize the physiology of osmotically regulated copeptin release and its half-life in
direct comparison with plasma AVP. Design Ninety-one healthy volunteers underwent a
standardized three-phase test protocol including (1) osmotic stimulation into the hypertonic …
whose measurement is more robust than that of AVP. Similar release and clearance
characteristics have been suggested promoting copeptin as a surrogate marker. Objective
To characterize the physiology of osmotically regulated copeptin release and its half-life in
direct comparison with plasma AVP. Design Ninety-one healthy volunteers underwent a
standardized three-phase test protocol including (1) osmotic stimulation into the hypertonic …
Context
Copeptin is the C-terminal fragment of the arginine vasopressin (AVP) prohormone whose measurement is more robust than that of AVP. Similar release and clearance characteristics have been suggested promoting copeptin as a surrogate marker.
Objective
To characterize the physiology of osmotically regulated copeptin release and its half-life in direct comparison with plasma AVP.
Design
Ninety-one healthy volunteers underwent a standardized three-phase test protocol including (1) osmotic stimulation into the hypertonic range by hypertonic-saline infusion followed by osmotic suppression via (2) oral water load and (3) subsequent glucose infusion. Plasma copeptin, AVP, serum sodium, and osmolality levels were measured in regular intervals.
Results
In phase 1, an increase in median osmotic pressure [289 (286; 291) to 311 (309; 314) mOsm/kg H2O] caused similar release kinetics of plasma copeptin [4 (3.1; 6) to 29.3 (18.6; 48.2) pmol/L] and AVP [1 (0.7; 1.6) to 10.3 (6.8; 18.8) pg/mL]. Subsequent osmotic suppression to 298 (295; 301) mOsm/kg at the end of phase 3 revealed markedly different decay kinetics between both peptides—an estimated initial half-life of copeptin being approximately 2 times longer than that of AVP (26 vs 12 minutes).
Conclusion
Copeptin is released in equimolar amounts with AVP in response to osmotic stimulation, suggesting its high potential as an AVP surrogate for differentiation of osmotic disorders. Furthermore, we here describe the decay kinetics of copeptin in response to osmotic depression enabling to identify a half-life for copeptin in direct comparison with AVP.
Oxford University Press