Possible Role of the Hypothalamic Melanocortin System to Induce Satiety by High Protein/low Carbohydrate Diets
Guest, Dolores Doane
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/84962
Description
Title
Possible Role of the Hypothalamic Melanocortin System to Induce Satiety by High Protein/low Carbohydrate Diets
Author(s)
Guest, Dolores Doane
Issue Date
2009
Doctoral Committee Chair(s)
Kelly A. Tappenden
J. Lee Beverly
Department of Study
Nutritional Sciences
Discipline
Nutritional Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Health Sciences, Nutrition
Language
eng
Abstract
The percentage of American adults, aged 20 years and older, who are overweight or obese continues to increase. High protein diets have been successful as weight reduction strategies, in part, because subjects report feeling more satiated and subsequently eat less. These diets are also reported to improve other clinical markers associated with obesity and metabolic syndrome such as insulin sensitivity, blood lipid profiles and waist circumference. The goal of the present research was to first characterize neuropeptide expression in the mediobasal hypothalamus (MBH) in animals fed large amounts of dietary protein. The neuropeptides profiled were those previously demonstrated to affect feeding behavior, either by reducing or inducing food intake. Results from this first study lead to our hypothesis that the greater satiety when a high protein/low carbohydrate diet is consumed is influenced, in part, by an increase in the activity of the melanocortin system, specifically the neuropeptide alpha-melanocyte stimulating hormone (alphaMSH) within the MBH. We then evaluated some characteristics of high protein diets that might induce these changes in neuropeptides. Soy protein was more effective than casein in reducing food intake, though no clear association between plasma amino acid levels and food intake were apparent. Finally, we sought to establish a causal association between increased melanocortin activity in the MBH and the reduction in food intake of high protein diets by evaluating the affects of a competitive MC4 receptor agonist (MTII) or antagonist (SHU9119). The effects of the agents were greater in the control diet and antagonism of the receptor returned the food intake of the high protein diet to the level of standard protein diet, while the agonist induced the same degree of decreased food intake of standard protein diet observed in the high protein diet fed animals. Together, these results support increased activity of the melanocortin system mediating the enhanced satiety experienced by those eating high protein/low carbohydrate diets.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
