A method using hypophysectomized-adrenodemedullated rats for the assay of small quantities of insulin is described.
If known quantities of insulin are added to plasma kept at room temperature overnight, they produce quantitatively similar effects on the rat as in the absence of plasma. The method allows determination of alteration in the insulin concentration of plasma.
The insulin concentration in peripheral blood plasma of fasting human subjects and dogs is lower than the minimal quantities of insulin which could be estimated by the present method.
The insulin concentrations in peripheral human plasma 90 to 120 minutes after meal are 0.2 to 0.3 milliunit per ml, and in normal dogs after intravenous injection of 20 g of glucose are 0.3 to 0.4 milliunit per ml.
The insulin concentrations in blood obtained from the superior pancreaticoduodenal vein in fasting dogs are 0.2 to 0.3 milliunit per ml, and in the blood from the pancreatic branch of splenic vein are 0.3 to 0.4 milliunit per ml.
View full abstract