Standard pork and rat crystalline insulin and fractions of rat islet of Langerhans were assayed for insulin content by the radioimmunoassay method. The results indicated that equal amounts of the crystalline insulin used in the standard preparations and the insulin present in the tissues assayed did not produce equal responses as measured by immunoassay, a finding which reflected unequal competition of the insulin present in the standards or tissues with the I125-labeled porcine insulin used as a tracer. The use of crystalline insulin of either kind as a standard to measure insulin in tissue resulted in an underestimation of the amount of insulin present. The pork standard created the greatest discrepancy when used in the measurement of insulin in rat tissue samples. A method is described that will estimate the amount of insulin present in tissue. The results of this method agreed closely with a method of estimating insulin content by electrophoresing the samples on polyacrylamide gels, staining, and scanning the gels.
|Original language||English (US)|
|Number of pages||11|
|Journal||The Journal of laboratory and clinical medicine|
|State||Published - Dec 1 1969|