Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Ryan, Peter L.

Committee Member

Rude, Brian J.

Committee Member

Feugang, Jean M. N.

Committee Member

Seo, Keun Seok.

Committee Member

Willard, Scott T.

Date of Degree

5-11-2013

Document Type

Dissertation - Open Access

Major

Veterinary Medical Science

Degree Name

Doctor of Philosophy (Ph.D)

College

College of Veterinary Medicine

Department

Veterinary Medical Science Program

Abstract

L-arginine is one of the most versatile amino acids due to the fact that it serves as a precursor for many molecules which have important roles in bodily functions including mammalian reproduction. The current studies sought to further examine the role that L-arginine has in mammalian reproduction utilizing both in vivo and in vitro approaches. In the first study, a novel bioluminescent murine pregnancy model was developed to monitor VEGFR2 transcription activity non-invasively in the fetoplacental unit. Secondly, the effect that dietary L-arginine supplementation has during mouse gestation was examined. L-arginine supplementation increased weight gain during the latter third of gestation, total litter size, number of implantation sites, and litter birth weight. Additionally, L-arginine supplementation increased VEGFR2 transcription activity in the fetoplacental unit which may create a more favorable environment for fetal survival. Moreover, the increased number of implantation sites observed suggests an effect of L-arginine at the level of the endometrium. To this end, the effect that L-arginine has on apoptosis and cell proliferation in an established endometrial cell line was examined. The addition of L-arginine at physiological (200 micromolar) and supra-physiological (800 micromolar) concentrations increased cell proliferation , and this effect was achieved through biosynthesis of polyamines and nitric oxide. L-arginine also decreased the proportion of cells that were experiencing mitochondrial mediated apoptosis, and it was observed that this decrease in mitochondrial mediated apoptosis was concurrent with increased phosphorylation of BAD protein, which induces apoptosis when not phosphorylated. The final study examined the ability of porcine uterine epithelial (PUE) cells to synthesize L-arginine from L-citrulline. L-citrulline was able to support PUE cell proliferation in the absence of L-arginine. Additionally, ASS-1 and ASL, L-arginine synthesizing enzymes, were expressed in PUE cells and were regulated by the presence of L-arginine and L-citrulline, respectively. This data would support the hypothesis that PUE cells may be able to convert L-citrulline to L-arginine. Together, the current findings along with the plethora of relevant literature provide further evidence for the role of L-arginine in mammalian reproduction and allow for new questions to be investigated regarding this particular amino acid’s role in mammalian reproduction.

URI

https://hdl.handle.net/11668/16624

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