Effect of glucoprivation on glutamate decarboxylase activity in the ventromedial nucleus.
Activity of the GABA-synthesizing enzyme, glutamate decarboxylase (GAD), was measured in brain areas involved in glucoregulation 60 min after a glucoprivie challenge. The rate of GAD activity in the ventromedial nucleus of the hypothalamus (VMN) increased in a dose-dependent manner in response to intraperitoneal injection of 2-deoxy-D-glucose (2-DG). The increase in VMN GAD activity was significantly correlated with an increase in food intake (r2 = .77, p less than 0.01). The increase in VMN GAD activity was not due to the higher food intake since rats receiving 2-DG and denied access to food also had elevated rates of VMN GAD activity. VMN GAD activity was increased 28% and 32% after intracerebroventricular injection of 2-DG or 5-thioglucose, respectively. The rates of GAD activity in the lateral hypothalamus and area postrema were not affected by either peripherally or centrally administered 2-DG. The increase in VMN GAD activity after glucoprivation may be involved in the regulation of blood glucose by influencing food intake.
Beverly
J L
JL
Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616.
Martin
R J
RJ
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D001931:Brain Mapping; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005968:Glutamate Decarboxylase / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology; D007026:Hypothalamic Area, Lateral / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014697:Ventromedial Hypothalamic Nucleus / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis*
D001786:Blood Glucose; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase