This application proposes a continuation of my neurobavioral analysis of glucagon's role in the control of postprandial satiety. The effects of glucagon on spontaneous meals will be investigated in free-feeding rats in order to characterize further the contexts in which it controls meal size, to elucidate its neuroendocrine mechanisms, and to establish its role in the regulation of body weight. The project's general goal is to advance understanding of the physiolo- gical controls of feeding. This is a central problem in the physiological psychology of motivation. Its solution is also prerequisite for the development of physiologically-based treatments of clinical disorders such as obesity, bulimia, and anorexia nervosa. These investigations are especially relevant in the view of the evidence that physiologic glucagon doses inhibit appetite in humans and that endogenous glucagon is necessary for the normal control of spontaneous meals in rats. The proposed experiments measure feeding in undisturbed free-feeding rats administered meal-contingent hepatic portal glucagon infusions. Both infusions and data collection are computer-controlled.
The specific aims of the project are to determine: (1) The infusion parameters maximizing glucagon's satiety effect. (2) Whether the liver is the site of glucagon's satiety effect. (3) Whether stimulation of fatty acid oxidation causes the satiety effects of exogenous and endogenous glucagon. (4) Whether prandial hepatic glycemic changes contribute to glucagon satiety. (5) The role of insulin-dependent glucose utilization in glucagon satiety. (6) Glucagon's effect in rats that are offered food choices. (7) The dose-response relation of the stimulatory effect on feeding of antagonism of endogenous glucagon by glucagon antibody infusion. (8) The effects of repeated meal-contingent glucagon infusions on food intake and body weight.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK032448-11
Application #
3230843
Study Section
Biopsychology Study Section (BPO)
Project Start
1982-09-01
Project End
1994-05-31
Budget Start
1992-06-01
Budget End
1993-05-31
Support Year
11
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Type
Schools of Medicine
DUNS #
201373169
City
New York
State
NY
Country
United States
Zip Code
10065
Geary, N; Asarian, L (2001) Estradiol increases glucagon's satiating potency in ovariectomized rats. Am J Physiol Regul Integr Comp Physiol 281:R1290-4
Geary, N (1999) Effects of glucagon, insulin, amylin and CGRP on feeding. Neuropeptides 33:400-5
Geary, N (1996) Failure of pulsatile infusion to increase glucagon's satiating potency. Physiol Behav 59:613-6
Surina-Baumgartner, D M; Langhans, W; Geary, N (1995) Hepatic portal insulin antibody infusion increases, but insulin does not alter, spontaneous meal size in rats. Am J Physiol 269:R978-82
Geary, N; Trace, D; Smith, G P (1995) Estradiol interacts with gastric or postgastric food stimuli to decrease sucrose ingestion in ovariectomized rats. Physiol Behav 57:155-8
Geary, N; Trace, D; McEwen, B et al. (1994) Cyclic estradiol replacement increases the satiety effect of CCK-8 in ovariectomized rats. Physiol Behav 56:281-9
Le Sauter, J; Geary, N (1993) [Pancreatic glucagon: physiological signal of postprandial satiety] Ann Endocrinol (Paris) 54:149-61
Geary, N; Le Sauter, J; Noh, U (1993) Glucagon acts in the liver to control spontaneous meal size in rats. Am J Physiol 264:R116-22
Geary, N; Fudge, J; Le Sauter, J (1992) Scheduled running wheel activity indexes the specificity of pharmacological anorexia. Behav Neural Biol 58:1-7
Geary, N; Kissileff, H R; Pi-Sunyer, F X et al. (1992) Individual, but not simultaneous, glucagon and cholecystokinin infusions inhibit feeding in men. Am J Physiol 262:R975-80

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