Lectins, calcium ionophore A23187 and peanut oil as deciduogenic agents in the uterus of pseudopregnant mice: effects of tranylcypromine, indomethacin, iproniazid and propranolol.
Intraluminal injections of lectins, including concanavalin A (Con A), wheatgerm lectin, and soybean lectin, Con A-Sepharose 4B beads, calcium ionophore A23187 or peanut oil into the left uterine horns of mice on day 4 of pseudopregnancy induced the formation of deciduomata and significantly increased the weight and alkaline phosphatase activity of uterine tissue on day 7 of pseudopregnancy. In contrast, injections of these materials into the uterine horns of non-pseudopregnant mice that had not been previously mated failed to induce similar responses. Tranylcypromine blocked the decidual cell reaction artificially induced by lectins, calcium ionophore A23187 and peanut oil in pseudopregnant mice. However, uterine responses observed after individual and concurrent injections with indomethacin, iproniazid, propranolol or progesterone indicated that this deciduoma-blocking effect may not be solely related to the ability of tranylcypromine to inhibit prostacyclin biosynthesis but may also involve catecholamines and luteolytic prostaglandins which interfere with decidualization on day 4 and day 6 of pseudopregnancy, respectively. A role for prostaglandins and uterine beta-adrenergic receptors, however, was implicated in the induction of decidualization because both indomethacin and propranolol blocked the response to peanut oil. The results suggested that the embryonic signal responsible for the induction of the decidual cell reaction in mice may involve surface interactions between the embryo and uterine luminal epithelium resulting in a stimulation of the uterus via glycoprotein receptors. A role for calcium was implicated in this phenomenon.