AJP - Regulatory, Integrative and Comparative Physiology, Vol 243, Issue 3 445-R449, Copyright © 1982 by American Physiological Society
Obesity-inducing hypothalamic knife cuts: effects on lipolysis and blood insulin levels
G. A. Bray, A. Sclafani and D. Novin
The effect of two experimental manipulations designed to mobilize lipids
from adipose tissue have been investigated in rats with parasagittal knife
cuts in the ventromedial hypothalamus (VMH). Those animals which displayed
hyperphagia during the initial 5 days VMH knife cuts were then restricted
in food intake to reduce body weights to levels comparable to that of the
sham-operated controls. Two weeks following the knife-cut lesions, or sham
operations, animals in the first experiment were exposed to the cold for 60
min, and those in the second experiment were injected with
2-deoxy-D-glucose (2-DG). The injections of 2-DG increased the level of
glycerol in the control animals but not in the animals with VMH knife cuts.
Both groups showed a rise in glucose. Plasma insulin and triglycerides were
the same in both groups. Exposure to the cold increased the level of
glycerol in both groups. The insulin levels were lower in the corresponding
groups with knife cuts. These studies show that VMH knife cuts do not
produce hyperinsulinemia in pair-gained rats.
