[Down regulation of insulin receptors in the rat liver in aging].

No decrease in the specific binding of 125I-insulin in the liver plasmatic membranes in response to insulin administration (2 units per 100 g/w) occurred in 24-26 month old rats whereas the response was obvious in 5-6 month old animals. The older animals showed a less obvious response of insulin receptors to 2-week administration of the hormone.