PRODUCTION OF PREMATURE DELIVERY IN PREGNANT RHESUS-MONKEYS BY ANDROSTENEDIONE INFUSION

The endocrine mechanisms involved in term and preterm delivery in prim ates, including pregnant women, are poorly understood. In the term mon key, fetal plasma androgen concentration rises to two hundred times th e maternal concentration which remains unchanged. Placental conversion of androgen to estrogen results in increased maternal plasma estrogen concentration at term in both pregnant nonhuman primates and women. I n the present study, continuous infusion of androstenedione to 0.8 ges tation monkeys resulted in the premature occurrence of labor-type myom etrial activity and increases in maternal plasma estrogen, oxytocin an d amnion fibronectin concentrations similar to those measured at norma l-term labor. Androstenedione induction of these normal-term biochemic al and endocrine changes accompanied by fetal membrane rupture, cervic al dilatation and live delivery provides a rich opportunity to study t he molecular and physiological mechanisms of both term and preterm lab or in primates.