Journal of Clinical Endocrinology & Metabolism, Vol 65, 116-121, Copyright © 1987 by Endocrine Society
Influence of infused hypertonic saline on the response to insulin- induced hypoglycemia in man
GK Adler and JA Majzoub
We studied the influence of a hypertonic saline infusion on the
counterregulatory response to insulin-induced hypoglycemia in nine normal
men. When given hypertonic saline, the men had less hypoglycemia in
response to insulin, both acutely and in the recovery phase (P less than
0.01), and released 34% more glucagon (P less than 0.05) than when they
were water loaded. The total integrated ACTH, cortisol, epinephrine,
norepinephrine, and GH responses to hypoglycemia were similar after saline
and water loading. After the saline load, the mean plasma vasopressin level
rose from 11.0 +/- 2.2 (+/- SEM) to 20.9 +/- 2.9 pg/mL in response to
insulin-induced hypoglycemia. In contrast, after the water load,
vasopressin levels were undetectable (less than 2 pg/mL) and they increased
only to 2.6 +/- 0.4 pg/mL with hypoglycemia. There was a significant
positive correlation between basal plasma vasopressin and nadir glucose
concentrations and a significant negative correlation between basal plasma
vasopressin and the integrated fall in glucose after insulin administration
(P less than 0.01 and P less than 0.025, respectively). The difference in
the glycemic response to insulin may be related to the high vasopressin
levels after saline loading, which could, either directly and/or through
enhanced glucagon release, increase hepatic glucose production and thus
limit the hypoglycemic response to insulin.
