The present invention relates to a chimeric nucleic acid molecule encoding a fusion protein having a human lutropin hormone-receptor domain and a human chorionic gonadotropin-.beta. subunit domain, the isolated human lutropin hormone-receptor/human chorionic gonadotropin-.beta. fusion protein, and antibodies which recognize part or all the domains of the fusion protein. Also provided are compositions having the human lutropin hormone-receptor/human chorionic gonadotropin-.beta. fusion protein and a pharmaceutical carrier and compositions including antibodies to the fusion protein and a pharmaceutical carrier. The present invention also relates to methods of treating androgen-excess-mediated disease conditions by administering to a subject an antibody to the human lutropin hormone-receptor/human chorionic gonadotropin-.beta. fusion protein under conditions suitable to treat the conditions, and methods of immunocontraception that involve administering to a subject the chimeric nucleic acid molecule encoding the human lutropin hormone receptor/human chorionic gonadotropin-.beta. fusion protein, the fusion protein in whole or in part, or antibodies thereto.