Effects of chronic intrahypothalamic infusion of insulin on food intake and diurnal meal patterning in the rat.
In Experiment 1, rats were chronically infused with insulin (2.7, 27, or 270 ng/hr) or 0.9% saline into the ventromedial (VMH), medial perifornical (PF), or lateral (LH) hypothalamus. VMH infusions of insulin caused a significant, dose-dependent decrease in food intake and body weight; PF infusion of insulin was less effective, but significant; whereas LH infusions of insulin were ineffective. In Experiment 2, rats were chronically infused with insulin (0.54 ng/hr) or 0.9% saline into the VMH, paraventricular (PVN), or posterior (PN) hypothalamic nucleus. Subjects that received VMH or PN infusions of insulin failed to regain weight lost as a result of surgery even 2 weeks after infusion; subjects that received PVN infusions of insulin regained their preoperative weights faster than did controls. All of the groups that received insulin significantly increased their daytime food intake during the infusion period and decreased their night food intake slightly; 24-hr food intake remained unchanged.
Committee on Biopsychology, University of Chicago, Illinois 60643.
M K
MK
McGowan
K M
KM
Andrews
J
J
Kelly
S P
SP
Grossman
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001931:Brain Mapping; D002940:Circadian Rhythm / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D002149:Energy Intake / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D007026:Hypothalamic Area, Lateral / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects*; D007276:Injections, Intraventricular; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects
D007328:Insulin