Heterologous radioimmunoassays for a semiquantitative analysis of al-microglobulin were developed, exploiting the binding between polyclonal rabbit or goat antisera against human, guinea pig, or rat almicroglobulin and ‘Z61-labeled human, guinea pig, or rat a,-microglobulin. Homologues of this protein were detected in human, guinea pig, Rhesus monkey, rat, mouse, rabbit, goat, horse, and cow se...