|
|
||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 3 697-R703, Copyright © 1990 by American Physiological Society
ARTICLES |
J. L. Beverly and R. J. Martin
Department of Physiological Sciences and Food Intake Laboratory, University of California, Davis 95616.
Changes in the activity of glutamate decarboxylase (GAD), the rate-limiting enzyme in gamma-aminobutyric acid synthesis, in response to insulin-induced hypoglycemia were measured in several brain areas involved in glucoregulation. A 20% increase in GAD activity in the ventromedial nucleus (VMN) of rats was measured 30 min after injections of insulin. The increase was significantly correlated with the decrease in serum glucose (r = -0.74) and increased food intake (r = 0.44). The increase in VMN GAD activity was linear between 5 and 30 min after insulin injection and coincided with the decline in serum glucose. Pretreatment with a gastric preload of a 50% glucose solution attenuated the decline in serum glucose, the increase in food intake, and the increase in GAD activity. Inhibition of protein synthesis by puromycin did not block the decrease in glucose, but neither the increase in GAD activity in the VMN nor the increase in food intake in response to insulin was observed. The increase in VMN GAD activity also was present 6 h after insulin injection if rats were denied access to food. No consistent changes in GAD activity were measured in any brain area other than the VMN. The results of these trials suggest that the increase in VMN GAD activity is associated with the decrease in serum glucose and may be involved in the increased feeding associated with insulin administration.
This article has been cited by other articles:
![]() |
J. L. Beverly, M. G. De Vries, S. D. Bouman, and L. M. Arseneau Noradrenergic and GABAergic systems in the medial hypothalamus are activated during hypoglycemia Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2001; 280(2): R563 - R569. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |