THE EFFECT OF ATROPINE ON INSULIN RELEASE CAUSED BY INTRAVENOUS GLUCOSE IN THE RHESUS MONKEY

Abstract

ABSTRACT Glucose was given as a rapid intravenous injection to fasted anaesthetized rhesus monkeys, and the concentrations of blood glucose and plasma insulin were measured. Glucose caused a biphasic insulin response. The first phase (which was short) occurred 1 min after the injection; the second was longer, and occurred 17 to 30 min after the injection. Following the control glucose injection, each animal was given atropine, and the insulin response to an identical glucose stimulus was measured. This produced a mean reduction of 45 % in the area under the curve of insulin release. Both phases of insulin release were inhibited by atropine. When glucose was given alone, its mean half-time of disappearance from the circulation (t1/2) was 25.4 (± 1.9 sem) min. After atropine the mean t1/2 was 36.6 (± 3.1 sem) min, a significant difference. It is suggested that the delayed rate of disappearance of glucose from the circulation is the result of inhibition of insulin release by atropine.