Diethylstilbestrol caused serum trypsin-inhibitory capacity (STIC) values to rise into the low-normal range in most studied heterozygotes with α1-antitrypsin deficiency, but never above 1.20 units; in control subjects, the stimulated STIC values exceeded 1.30 units. Subjects with homozygous antitrypsin deficiency did not respond to diethylstilbestrol. Lack of response to 3 mg of diethylstilbestrol daily for two weeks in a patient with 1.20 units or less of antitrypsin activity indicates that the patient's antitrypsin level is already maximally stimulated by his disease, and confirms a dagnosis of heterozygous α1-antitrypsin deficiency. Women receiving oral contraceptive medication or other estrogenic hormones whose random antitrypsin assay shows a level of 1.20 units or less should be suspected of carrying the abnormal gene for antitrypsin deficiency.
Lieberman J, Mittman C, Kent JR. Screening for Heterozygous α1-Antitrypsin DeficiencyIII. A Provocative Test With Diethylstilbestrol and Effect of Oral Contraceptives. JAMA. 1971;217(9):1198-1206. doi:10.1001/jama.1971.03190090020006