Abstract
A sensitive and specific radioimmunoassay for human α-lactalbumin, a major milk protein, is described. Some normal men and women have detectable levels of α-lactalbumin in their blood. High values are found in nursing mothers and many patients with galactorrhea. α-Lactalbumin is found in some breast cancer organ cultures. In addition, α-lactalbumin output was stimulated by ovine prolactin in 2 of the 19 tumors studied.