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

Abstract

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.

PIP: The luteolytic effect of iproniazid, a potent monoamine oxidase inhibitor, during pseudopregnancy and pregnancy was studied in rats. A single injection (200 mg/kg) of iproniazid induced luteolysis and caused lysis of deciduomata. Resorption of viable embryos was also observed. The administration of prolactin or progesterone countered the antifertility effects of the drug. Neither a single or double injection of iproiazid on Days 12 and 14 of pregnancy produced deleterious effects on the growth of fetuses, placentas, ovaries and corpus luteum. This suggests that iproniazid exerts its luteolytic effect only when the hypothalamic-pituitary complex is involved in the maintenance of pregnancy.