Diabetes, Vol 36, Issue 1 20-26, Copyright © 1987 by American Diabetes Association
Defective epinephrine and growth hormone responses in type I diabetes are stimulus specific
BR Hirsch and H Shamoon
The counterregulatory hormone responses to hypoglycemia and a non-glucose
stimulus, exercise, were evaluated in 18 subjects with type I diabetes and
in 9 normal controls. Subjects with diabetes had no overt neuropathy, with
R-R variations and postural plasma norepinephrine increments that were
similar to those of controls. The diabetic subjects exhibited normal
increments in plasma growth hormone (GH), norepinephrine, and cortisol but
blunted or absent responses in plasma epinephrine and glucagon when
hypoglycemia was severe (less than 40 mg/dl). During a 60-min clamped
reduction in plasma glucose at approximately 65 mg/dl, plasma GH and
epinephrine increased 6- to 15-fold in controls but 2- to 4-fold in
diabetics (P less than .05). However, when subjects were exercised at this
plasma glucose level (50 W for 10 min), plasma epinephrine and GH in
diabetics rose markedly by 150-400% to attain the peaks reached by the
controls. Plasma norepinephrine and cortisol increased to similar levels in
both groups, and plasma glucagon was not significantly changed. We conclude
that epinephrine and GH secretion in response to hypoglycemia are reduced
in type I diabetes but that these defects are stimulus specific because the
responses to exercise are not reduced.