Messung von Insulinaktivität an isolierten Fettzellen

Abstract

A technically simple method is described for the measurement of insulin activity with fat cells isolated with the aid of collagenase. Compared with the determination of insulin with intact fat tissue, the fat cell method is more sensitive, considerably more precise, and a larger number of directly comparable measurements can be made. The maximal deviation of a single measurement is less than 20%. As in the test with fat tissue, the practically linear region of the dose-response curve on a double logarithmic scale covers an increase of a power of 10 in the insulin dose. The fat cells are stimulated by concentrations of insulin as low as 1 to 3 [mu]U/ml. With isolated A- and B-chains, recombination products and chemically modified insulin, the method has the same specificity as the test with fat tissue; there was no difference in specificity towards insulin from the hag fish. It is not known whether a similar correspondence exists for other naturally occurring insulins.