Abstract: The use of copeptin as diagnostic marker for the determination of the release of vasopressin, especially in connection with disorders associated with non-physiological alterations of vasopressin release from the neurohypophysis, especially for detection and early detection, diagnosing and monitoring of the course of cardiovascular diseases, renal and pulmonary diseases as well as shock, including septic shock, sepsis and diseases/disorders of the central nervous system and neurodegenerative diseases.

Abstract: Vasopressin analogues of formula (I) ##STR1## wherein X is (S)-2-amino-2-methyl-butanoic acid (CaMeAbu) or Valine (Val), Y is Thienylalanine (Thi) or Methionine (Met), Z is D-Phenylalanine (D-Phe) or D-Thienylalanine (Thi) or D-Tyrosine (D-Tyr), are disclosed. Pharmaceutical preparations comprising a vasopressin analogue of the invention as active ingredient are disclosed and exemplified by oral preparations, nasal preparations, and intravenous preparations. The vasopressin analogues of the invention are intended for use as a medicament, specially an antidiuretic agent. The antidiuretic agent is preferably used for the treatment of diabetes insipidus or enuresis.