Mice deficient in oxytocin (OT) (OT KO), those that do not synthesize or release OT at any point in the life cycle, have shown significantly enhanced ingestion of sweet (sucrose and saccharin) and non-sweet carbohydrate-containing solutions (Polycose and cornstarch) as compared to wildtype (WT) mice of the same C57BL/6 background. The purpose of this work is two-fold: to determine if the effects observed with sweet and non-sweet carbohydrate-containing solutions extend to a palatable non-carbohydrate containing emulsified fat solution (Intralipid), and to further elucidate the drinking behavior of WT and OT KO mice exposed to sucrose solutions. Mice were exposed to a variety of two-bottle access tests to compare ingestion of Intralipid, a fat-containing emulsion, as well as sucrose and aversive (sodium chloride (NaCl) and citric acid) solutions mixed with sucrose.
On the first day of exposure to Intralipid OT KO animals consumed significantly greater volumes of Intralipid as compared to WT mice. Animals showed preference for the Intralipid emulsion over water at a variety of concentrations, however, no genotypic differences were observed in Intralipid ingestion beyond the first exposure day, suggesting that the increased ingestion of palatable liquids observed in OT KO mice does not extend to Intralipid solutions.
OT KO mice continually consumed more 10% sucrose than WT mice during repeated four-day trials and during a two-week trial. Sucrose bottle placement did not have a significant effect on sucrose consumption. OT KO mice also consumed significantly more sucrose at concentrations of 0.625%, 1.25%, 2.5%, and 5% during four-day trials. Similar drinking patterns were observed in male and female animals and across generations.
When exposed to two-bottle access to 0.5M NaCl or 30mM citric acid mixed with 10% sucrose and water, OT KO animals consumed more of the aversive solution mixed with 10% sucrose than WT counterparts.
The results of this thesis suggest that OT plays a role in the ingestion of sweet carbohydrate-containing solutions. However, it appears that these effects do not extend to the ingestion of Intralipid, a palatable fat-containing emulsion. The exact function of OT in these ingestion behaviors has yet to be determined.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04232007-135209 |
| Date | 27 April 2007 |
| Creators | Miedlar, Julie A. |
| Contributors | Samuel M. Poloyac, PharmD, PhD, Regis R. Vollmer, Bankim A. Bhatt, Janet A. Amico, MD, Linda Rinaman, PhD |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04232007-135209/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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