The possible mode of action of iproniazid. I. Differential luteolytic effect of iproniazid before and after the establishment of placental adolescence.

Iproniazid, a very specific monoamine oxidase inhibitor, at a dose level of 200 mg/kg body weight induced luteolysis and caused lysis of deciduomata as well as resorption of the established embryos. Exogenous replacement of prolactin, a most consistent stimulant of the endocrine functioning of corpus luteum, or progesterone absolutely reversed the adversity developed following iproniazid injection. Moreover, failure of iproniazid even at a higher dose level in the deviation of the normal sequence of pregnancy after the establishment of placental adolescence strongly tempting to suggest that iproniazid could only show its luteolytic effect when the hypothalamic-pituitary complex is exclusively involved in the maintennance of pregnancy.