Effect of insulin on the exaggerated glucagon response to arginine stimulation in diabetes mellitus.

The effect of insulin on the glucagon response to intravenous arginine was studied in eight juvenile-type and six adult-onset diabetics. In the juvenile-type diabetics, concomitant administration of insulin significantly blunted the glucagon response from a mean maximal rise of 310 +/- 54 pg./ml. to only 184 +/- 39 pg./ml. (p less than 0.01), about the same as in nondiabetics. In the adult-onset patients, however, insulin had no effect, the mean maximal rise being 250 +/- 50 pg./ml. without insulin and 307 +/- 71 pg./ml. with insulin (N.S.). This study demonstrates that in juvenile-type diabetics concomitant administration of supraphysiologic quantities of insulin can reduce the exaggerated glucagon response to intravenous arginine to normal, whereas in the adult-type group, it has no apparent effect.