AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 4 745-R749, Copyright © 1984 by American Physiological Society
Elevated postprandial insulin levels do not induce satiety in normal-weight humans
R. Woo, H. R. Kissileff and F. X. Pi-Sunyer
To determine whether an elevated insulin level contributes to satiety, two
experiments were conducted using a covert system of monitoring food intake.
Normal-weight volunteers received intravenous infusion of either 0.15 M
saline or a mixture of glucose and insulin during a single-course meal. In
the first group, the glucose-insulin infusion (0.03 U insulin X kg-1 X h-1
and 0.25 g glucose X kg-1 X h-1) was begun 30 min before the start of the
test meal and ended 15 min after subjects had voluntarily stopped eating.
Plasma insulin was raised threefold, and glucose increased 20 mg/dl above
preinfusion base line at time of eating. In the second group, the
glucose-insulin mixture (insulin bolus of 12 mU/kg plus 0.03 U insulin X
kg-1 X h-1 and 0.125 g glucose X kg-1 X h-1) was delivered 12 min after an
appetizer was served and just as the test meal began. This infusion was
stopped 12 min after the end of the meal. Serum insulin was fourfold higher
than saline infusion levels at onset of eating, but glucose remained the
same. The changes induced in these studies by the glucose-insulin infusions
mimicked normal insulin and glucose levels seen shortly before satiation is
complete in a meal. No effect on meal size or duration was observed.
Therefore normal postprandial elevation of insulin is unlikely to signal
satiety in humans.
