1. Department of Biochemistry, Molecular Biology and Cell Biology (A.D.B., K.E.M.), Evanston, Illinois 60208;
2. Center for Reproductive Science (A.D.B., K.E.M.), Northwestern University, Evanston, Illinois 60208;
3. Reproductive Endocrine Unit (A.M.), Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114