Diabetes, Vol 26, Issue 5 445-452, Copyright © 1977 by American Diabetes Association
A test of the hypothesis that the rate of fall in glucose concentration triggers counterregulatory hormonal responses in man
RA DeFronzo, R Andres, TA Bedsoe, G Boden, GA Faloona and JD Tobin
The hypothesis that the rate of fall in glucose concentration triggers
counterregulatory hormonal responses was tested in five subjects following
one hour of sustained hyperglycemia. Despite a rapidly falling blood
glucose concentration, no increase in plasma growth hormone, cortisol,
glucagon, or catecholamines occurred as long as the blood glucose
concentration remained above fasting levels. Plasma growth hormone,
cortisol, and catecholamines were not released until the mean blood glucose
reached 28 mg./100 ml., 39 mg./100 ml., and 39 mg./100 ml., respectively,
below the fasting level. Plasma glucagon was suppressed during the period
of hyperglycemia. As the blood glucose concentration fell below basal
levels, a progressive increase in glucagon occurred. Plasma glucagon
returned to fasting values when the nadir in blood glucose was attained.
During the period of rapidly falling blood glucose, only plasma insulin
showed any change; its response lagged behind the decline in blood glucose.
By the time the fasting glucose level was attained, the plasma insulin was
still almost three times the basal level. We concluded that under our
experimental conditions the rate of fall in blood glucose and the degree of
hypoglycemia achieved is primarily determined by the plasma insulin
concentration.