Summary
Insulin-induced hypoglycemia causes an increase in plasma vasopressin (AVP) in healthy
subjects but the response in diabetics is not established. We investigated the effect
of insulin-induced hypoglycemia on ten insulin-dependent diabetics with asymptomatic
hypoglycemia, and compared the results with those for seven healthy subjects. The
lack of adrenergic symptoms of hypoglycemia in insulin dependent diabetics being attributed
to a diminished β-adrenergic sensitivity, the effect of isoprenaline infusion was
investigated as control.
Insulin-induced hypoglycemia resulted in both populations in significant increase
(P % 0.01) in AVP in addition to significant increases in heart rate, plasma epinephrine
(E), norepenephrine (NE) and cortisol (COR). Effective osmolality and mean arterial
blood pressure did not vary. Diabetics showed smaller increase in AVP (P % 0.01) and
heart rate (P % 0.05) than controls. Maximal E, NE and COR values did not differ between
the two populations. Isoprenaline infusion resulted in increase in heart rate and
plasma renin activity, but AVP and COR did not vary in the two populations.
In conclusion, insulin-induced hypoglycemia released AVP in diabetics with asymptomatic
hypoglycemia, but the response was weaker than in healthy subjects. A causal hypothalamic
alteration of β-adrenergic or glycopenia sensitivity is discussed.
Key words
Arginine Vasopressin - Insulin Dependent Diabetics - Insulin-Induced Hypoglycemia
