Inhibition of vasopressin effects on the uterus by a synthetic analogue.

A synthetic analogue, deamino-ethyl-oxytocin, which competitively inhibits vasopressin action on uterine activity both in vitro and in animal experiments was developed. The uterine effect of this analogue was studied during the recording of intrauterine pressure in 16 gynecologically healthy women. Increased uterine activity and dysmenorrhea-like pain was induced by infusing lysine vasopressin in a dose of 0.08 microgram/min. Deamino-ethyl-oxytocin inhibited vasopressin action, the threshold dose being approximately 200 micrograms given as a single intravenous injection for about 20 minutes. When given intranasally the drug was also shown to be effective in inhibiting vasopressin-induced uterine activity and symptoms. These results suggest that deamino-ethyl-oxytocin could be of therapeutic value in primary dysmenorrhea, a condition associated with increased vasopressin secretion.