Abstract
I131 labelled-insulin has been administered in tracer doses to rats and rabbits, intravenously or intraperitoneally.
Firstly, the localization of insulin-I131 into organs was investigated. Injecting intravenously, the kidneys, liver and also muscles were found to be the major regulator of the fate of injected insulin-I131, whereas there was no affinity to the brain. Injecting intraperitoneally, in the experiment, it was clearly revealed that affinity of insulin-I131 to the muscles was increased rather than that of administered insulin-I131 by intravenous injection.
Secondly, it was found that the major portion of the intracellular insulin-I131 was bound to mitochondria and microsome fraction, but not to nuclear fraction.
In conclusion, the significance of these investigations was discussed on the role of administered insulin-I131 in reference to insulin action or to its metabolism.
The posibility that the mechanism of insulin action, as a whole, will be connected with intracellular particles, particularly with mitochondria, will remain to be solved in the future.
