ECE2015 Eposter Presentations Pituitary: basic and neuroendocrinology (62 abstracts)
1Universitätsspital Basel, Basel, Switzerland; 2Universitätsklinikum Würzburg, Würzburg, Germany; 3Universitäts-Kinderspital beider Basel, Basel, Switzerland; 4Spital Uster, Uster, Switzerland; 5Universität Leipzig, Leipzig, Germany.
Background: Copeptin is the C-terminal portion of the precursor of vasopressin. In contrast to vasopressin copeptin is stable in vitro and easy to measure. Similar kinetics of both peptides have been described in different trials. However, the physiological area of normality of copeptin has never been evaluated.
Methods: We measured plasma copeptin, sodium, and osmolality levels in 93 healthy volunteers at baseline, during/after i.v. infusion of 3% saline until a sodium level of at least 150 mmol/l was reached, and during/after an oral waterload/i.v. infusion of glucose 5%. In total, 419 (median 12) measurements per patient were performed.
Results: Median age of the study participants was 28 years (range 2054 years) with a balanced gender distribution male/female (46/47). Upon hypertonic saline infusion plasma sodium levels increased from a median of 140 mmol/l (S.D. 2.21) to 152 mmol/l (S.D. 2.44), plasma osmolality from 293 mOsmol/kg (S.D. 6.62.) to 317 mOsmol/kg (S.D. 6.4) and plasma copeptin from 4.1 pmol (S.D. 4.56) to 34.2 pmol/l (S.D. 31.9). The maximal value of copeptin was reached after 150 min (S.D. 28.1), without a time lag to the maximum of plasma sodium or osmolality (reached after 145 (33.9) and 150 (27.4) min respectively). There was a moderate to strong positive correlation between plasma copeptin and plasma sodium (r=0.58, P<0.05) and plasma copeptin and plasma osmolality (r=0.48, P<0.05).
Conclusion: There is a correlation between plasma copeptin, plasma sodium, and plasma osmolality levels from normo-to-hyperosmolar states.
Disclosure: SNF Prof. M Christ-Crain, Thermo Fisher Scientific.