A quantitative evaluation of the relative efficiency of gelatine and albumin in preventing insulin adsorption to glass.

Albumin has been found to be more effective than gelatine in preventing insulin loss from insulin containing solutions. It is probable that this has led to falsely elevated levels of insulin-like activity (ILA) reported with bio-assays. Preparations of crystalline human albumin have been found to be free from ILA and from insulin measured by the radio-immuno-assay. Other human albumin prepared by acid-ethanol extraction (that has been shown previously to contain insulin antagonistic properties on the isolated rat hemidiaphragm) has contained significant ILA on the isolated rat fat pad and also contained insulin demonstrable by radio-immuno-assay.