No description available.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / "May 2008" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 70-82). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [42]-50).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 70-82). Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, Department of Neurobiology, Pharmacology, and Physiology, June 2000. / Includes bibliographical references. Also available on the Internet.

Understanding the central nervous systems role in appetite regulation is crucial to cure the obesity epidemic, which is more prevalent than any disease in the United States. Central appetite regulators, known as neuropeptides, are pivotal in understanding appetite regulation. Neuropeptide Y (NPY), a 36 amino acid peptide, plays a major role in regulating the hunger signals from the brain. In all vertebrates studied, it is a strong orexigenic neurotransmitter located throughout multiple nuclei of the hypothalamus. Peripheral hormones associated with hunger are able to activate NPY neurons in the arcuate nucleus, which leads to a cascade of events that activate orexigenic neurons throughout the hypothalamus. Although extensive research has gone into understanding the role of NPY in appetite regulation, the effects of macronutrient composition of diets on NPY function have not been elucidated in non-mammalian species. This research investigates how food intake is affected by dietary macronutrient composition in broiler type chickens that are fed three varying macronutrient diets: high carbohydrate (22% CP, 3000kcal/kg) a broiler starter diet, high fat (60% ME from lard), high protein 30%CP). All diets were formulated to be isocaloric. When chicks are fed the high fat diet central NPY administration has a greater effect on feed intake compared to both the basal and high protein diet. Regardless of what diet the chick is fed from hatch, if they are switched to one of the other two diets post central administration of NPY the high fat diet stimulated feed intake for the longest duration. Although, NPY had the strongest orexigenic effect on chicks fed the high fat diet, in a choice diet situation broiler chicks chose the high protein diet, independent of central NPY administration. / Master of Science

Peptides that regulate feeding behavior via the brain may also regulate energy storage and expenditure in the adipose tissue, a system collectively known as the "brain-fat axis". Neuropeptide Y (NPY) is orexigenic and promotes adipogenesis in both birds and mammals, although mechanisms in adipose tissue are unclear. The first objective was thus to evaluate effects of NPY on chick preadipocyte proliferation and differentiation. Preadipocytes were treated with NPY and gene expression and cellular proliferation were evaluated. Cells were also treated with NPY during differentiation and harvested during the later stages. With increased gene expression of proliferation markers in preadipocytes, and during differentiation increased expression of adipogenesis-associated factors, increased lipid accumulation, and increased activity of an adipogenic enzyme, glycerol-3-phosphate dehydrogenase, results suggest that NPY may enhance preadipocyte activity and adipogenesis and promotes lipid accumulation throughout chicken adipocyte differentiation. Another appetite-regulatory peptide, alpha-melanocyte stimulating hormone (α-MSH), is anorexigenic and mediates lipolysis in adipose tissue, but effects on fat in avians are unreported. The second objective was thus to determine the effects of exogenous α-MSH on adipose tissue physiology in broiler chicks. Chicks were intraperitoneally injected with α-MSH and adipose tissue and plasma collected. Cells isolated from abdominal fat of a different set of chicks were treated with α-MSH. Results suggest that α-MSH increases lipolysis and reduces adipogenesis in chick adipose tissue. Collectively, results of this research provide insights on how appetite-regulatory peptides like NPY and α-MSH affect adipose tissue physiology, thereby playing important roles in regulating whole-body energy balance. / Master of Science

<p>Neuropeptide Y (NPY) is an abundant neurotransmitter in the nervous system and forms a family of evolutionarily related peptides together with peptide YY (PYY), pancreatic polypeptide (PP) and polypeptide Y (PY). These peptides are ligands to a family of receptors that mediate a wide range of physiological effects including stimulation of appetite. This work describes the molecular cloning of four novel NPY receptors.</p><p>In rat a receptor called PP1, later renamed Y₄, was cloned and characterized. It displays the highest amino acid sequence identity to the Y₁ receptor. Rat Y₄ differs extensively from human Y₄, cloned subsequently, in both pharmacological properties, tissue distribution, and amino acid sequence with only 75% identity. Rat and human Y₄are the most diverged orthologues in the NPY receptor family.</p><p>In guinea pig, the y₆ receptor gene was found to be a pseudogene with several frameshift mutations. The gene is a pseudogene in human and pig too, but seems to give rise to a functional receptor in mouse and rabbit. This unusual evolutionary situa- tion may be due to inactivation of the gene in a mammalian ancestor and then restoration of expression in mouse and rabbit, but perhaps more likely due to independent inactivations in guinea pig, human and pig.</p><p>In zebrafish, two new intronless receptor genes were cloned. Sequence comparisons suggest that both receptors are distinct from the mammalian receptors Y₁, Y₄ and y₆, hence they were named Ya and Yb. Chromosomal localization provides further support that Ya and Yb may be distinct subtypes. </p><p>The discoveries of the rat Y₄ and zebrafish Ya and Yb receptors were unexpected and show that the NPY receptor family is larger than previously thought.</p>