IMMUNOLOGICAL SPECIFICITY OF HUMAN INSULIN: APPLICATION TO IMMUNOASSAY OF INSULIN

Abstract

Previous observations of variable and occasionally marked differences in reaction of beef insulin and human insulin competing with beef insulin-I131 in human antibeef, pork insulin sera and in guinea pig antibeef insulin sera are confirmed and extended. Antisera from guinea pigs immunized with pork insulin exhibit close similarity of reaction with pork and human insulin. In 2 antisera, pork and human insulin reacted identically when competing against the anti-body-binding of pork insulin-I131. Employment of these antisera for the immunoassy of endogenous plasma insulin in man obviates the necessity for employment of human insulin as a standard. Human insulin (Fisher), previously estimated at 27. 3% insulin by weight, was assayed against pure human insulin (Cambridge) as standard. Present results confirm the accuracy of the previous estimate for immuno-logically active insulin content of the Fisher preparation.