[The effect of vasopressin analogs on water metabolism]

The effects of naturally occurring lysine and arginine vasopressins (LVP and AVP) were compared with those of 1-deamino-8-D-arginine-vasopressin (dDAVP) and 1-deamino-4-valine-D-arginine-vasopressin (dVDAVP). The changes of minute diuresis, urinary osmolarity and the duration of action were followed. dDAVP and dVDAVP in a single intravenous and intranasal dose decreased the diuresis more markedly (3.5-fold) and for a longer duration (3.3-fold) than did LVP in patients with central diabetes insipidus. The administration of dDAVP and dVDAVP in the form of sublingual tablets also proved to be effective, where dVDAVP acted more markedly and longer (16 hrs) than dDAVP (12 hrs) in a single dose of 30 micrograms. During one week of sublingual dDAVP administration, the accumulation of the drug was indicated by the gradual decrease of diuresis and the increase of urine osmolarity. The misuse of such highly active drugs may even result in iatrogenic inappropriate ADH syndrome (Schwartz-Bartter). The danger of this syndrome will be demonstrated in a case history. Some more recently synthesized vasopressin analogues with antagonistic action on the diuresis may have an important role in the therapy of Schwartz-Bartter syndrome. The authors present their results with one of these antagonists [1-(beta-mercapto-beta, beta-cyclopentamethylene-propionic acid), 2-O-ethyltyrosine, 4-valine] arginine vasopressin (d/CH2/5Tyr/Et/VAVP) both in Brattleboro and in R-Amsterdam rats. This analogue blocks the antidiuretic effect of both exogenous and endogenous vasopressin.