The effect of insulin on vascular reactivity to norepinephrine.

The effect of insulin on the vasoconstrictor response to norepinephrine of the resistance bed of the isolated perfused rat tail has been studied. Insulin produced a significant attenuation of this response in concentrations of both 120 mU./ml. and 150 micronU./ml. It is suggested that this effect may be relevant to the hypotensive action of insulin observed in diabetics.