Human Chorionic Gonadotropin-Like Substance in Nonendocrine Tissues of Normal Subjects

By means of two assay systems, a beta chain human chorionic gonadotropin radioimmunoassay and a radioreceptor gonadotropin assay, a chorionic gonadotropin-like substance was demonstrated in extracts of liver and colon obtained at autopsy from three patients who died of nonneoplastic disease. In contrast to placental chorionic gonadotropin, colon and liver chorionic gonadotropin was not bound to concanavalin A-Sepharose columns, indicating that this substance possessed little or no carbohydrate. Previous workers demonstrated that desialylated human chorionic gonadotropin possesses little or no bioactivity in vivo but retains full radioreceptor and radioimmunoassay activity in vitro. Our data suggest that the genome responsible for the human chorionic gonadotropin production is not completely suppressed in adult nonendocrine tissues, and that the chorionic gonadotropin produced by colon and liver has little or no bioactivity in vivo because of its low carbohydrate content. Since many normal tissues produce chorionic gonadotropin, bioactivity may be modulated by regulation of carbohydrate content.