Copeptin

• OMIM: 192 340
• UniProt: P01185
• MGI: 88121

Copeptin ( C-terminal also proAVP, CT proAVP ) is composed of 39 amino acids, glycosylated peptide, which together with vasopressin (also known as AVP or antidiuretic hormone) and neurophysin II is synthesized as a prohormone in the hypothalamus ( Präprovasopressin ). Has Stepwise proteolytic cleavage of the prohormone release of the peptides vasopressin, neurophysin II and copeptin in equimolar quantities to be adjusted. Copeptin therefore arises from cleavage of the C-terminal part of the prohormone.

The physiological significance of copeptin is not yet fully understood. Discussed participation during the folding and transport of the maturing vasopressin from the hypothalamus to the neurohypophysis. After receiving the stimulus (osmotic stimulus or stress reaction) copeptin is released together with vasopressin and neurophysin II from the Neurohypohyse in the bloodstream.

Copeptin values ​​are particularly serious conditions such as sepsis, but, for example, in heart failure, increased in patients.

Copeptin, unlike AVP, in serum and EDTA plasma at room temperature for 7 days stable.

Diagnostics

Copeptin is used because of its biosynthesis and its properties as an alternative biomarker for AVP- determination for the diagnosis of various diseases.

An advantage of copeptin for the diagnosis is the relative stability of the analyte. Unlike Copeptin the hormonally active vasopressin is a small ( 9 amino acids ) and very unstable molecule. To ensure a valid measurement of vasopressin is recommended that the blood collection with pre-chilled tubes (excluding EDTA plasma ), the sample is cooled to transport and store at -20 ° C. The processing of blood samples, in which the vasopressin content is to be determined, is also time consuming and technically demanding. This has been the application of vasopressin measurements in routine clinical practice, although often displayed and for the patient of the benefit is limited. Copeptin, however, is easily measurable both in blood and in plasma and therefore stable. Because copeptin and Vasopresssin be split in the same ratio from the prohormone, copeptin is considered a surrogate marker for the more difficult to be determined vasopressin. Due to its technical advantages of the determination of copeptin in various indications has already been incorporated into the routine.

So can be improved by a combination of copeptin and troponin early diagnosis of myocardial infarction. Other studies focus on the role of copeptin in stroke. Here's a link between copeptin values ​​and the prognosis and mortality of the disease is seen. Copeptin can also be used as a biomarker for risk of pneumonia or differential diagnosis in central diabetes insipidus or polyuria polydipsia - syndrome.