Hormonal imprinting by steroids: a single neonatal treatment with diethylstilbestrol or allylestrenol gives rise to a lasting decrease in the number of rat uterine receptors.

Binding of hormone by the uterine receptors of 6 week old rats treated with diethylstilbestrol (DES) or allylestrenol (AE) in neonatal age differed considerably from the controls. Both pretreatments accounted for a decrease in the number of Type II binding sites for estradiol without altering receptor affinity. It follows that steroids, too, are able to induce a hormonal imprinting during the critical stage of receptor maturation.