AJP - Endocrinology and Metabolism, Vol 258, Issue 3 E476-E481, Copyright © 1990 by American Physiological Society
Effects of glucose, 2-deoxyglucose, phlorizin, and insulin on food intake of lean and fatty rats
S. Tsujii and G. A. Bray
Department of Medicine, University of Southern California, Los Angeles 90033.
Glucose, 2-deoxyglucose, phlorizin, and insulin were injected into the
third ventricle of lean and fatty rats, and food intake recorded hourly for
the next 6 h. In the lean rats, there was a significant but unimpressive
decrease in food intake after the intraventricular injection of glucose,
but there was no effect of glucose in the fatty rat. Phlorizin in the
lowest dose (10 micrograms) increased the food intake in lean animals at 1
and 2 h, and all three doses increased it significantly at 6 h after
intraventricular injection. The fatty rat, in contrast, showed no response
to phlorizin. 2-Deoxyglucose showed a dose-related stimulation of food
intake in the lean rats at 1, 2, 3, and 6 h after injection. In the fatty
rat, there was no significant effect on food intake at any dose. The
intraventricular injection of insulin had no effect on food intake in
either the lean or fatty rats. These studies indicate that
glucose-responding systems in the region of the third ventricle are
defective in the fatty rat to signals that normally increase or decrease
food intake in lean animals.
