An assay of insulin by fibril formation from small samples of pancreas

Biochemistry of the Protein Hormones

“…Several chemical assay methods for insulin have been proposed. Grodsky (244) has made use of the fibril-forming property of the hormone; when pancreatic extracts are seeded under appropriate conditions with freshly prepared fibrils, insulin precipitates almost quantitatively and can be es timated by ultraviolet absorption ; the source of the insulin fibrils used for seeding is unimportant. This procedure has been applied as an assay in beef, pig, cat, and rat pancreas, and the values found were comparable to those obtained with biological methods.…”

A method for the assay of insulin by paper chromatography

“…Wellcome Re8earch Laboratoriea, Biological Divi8on, Langley Court, Beckenham, Kent (Received 1 August 1958) Methods for the assay of insulin in vitro have appeared at intervals in the literature. Among the most familiar are the fibril-precipitation method of Waugh, Thompson & Weimer (1950) and the more recent version of the same method (Grodsky, 1958). The former method was the subject of an investigation by Foster, Macdonald & Smart (1951), who, although able to obtain reliable results in assays on freshly prepared solutions of insulin, protamine insulin and commercial concentrates, reported failure with solutions of low-potency insulin (11 units/mg.…”