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dc.contributor.advisorMcMillen, Carolineen
dc.contributor.authorMuhlhausler, Beverly Saraen
dc.description.abstractBased on a large series of epidemiological studies, it has been proposed that exposure to an increased nutrient supply before birth increases the risk of developing obesity in postnatal life. The physiological mechanisms underlying the association between increased nutrition before birth and later obesity are, however, poorly understood. This thesis has investigated the impact of an increased fetal nutrient supply on the programming of key systems within the appetite - regulating network and / or the adipocytes before and after birth. The studies in this thesis have demonstrated that plasma concentrations of the adipostatic hormone leptin are directly related to adiposity and the size of adipose cells in fetuses of ewes fed at or above maintenance energy requirements, which suggests that leptin may act as a peripheral signal of fat mass before birth. It has also been demonstrated that the components of the central network for appetite regulation are expressed in the hypothalamus of the fetal sheep from at least 110 d gestation ( term = 150 ± 3 d gestation ), and that the expression of the appetite - regulating neuropeptides is responsive to signals of increased nutrient supply before birth. This thesis has also demonstrated that an increase in maternal nutrition in late pregnancy results in increases in both food intake and glucose concentrations in the lamb in early postnatal life and in a significant increase in subcutaneous adiposity on postnatal day 30. Importantly, increased maternal nutrition resulted in an altered relationship between signals of increased fat mass and nutrition and expression of a central appetiteinhibitory neuropeptide, CART, in the lamb hypothalamus. It was also demonstrated that there was an interaction between the prenatal and postnatal nutritional environments in the determination of lipogenesis in the early postnatal period. The findings presented in this thesis provide evidence that programmed changes to the sensitivity of the appetite - regulating neuropeptides to signals of increased adiposity and nutritional status in early postnatal life are an important part of the physiological pathway through which exposure to an increased nutrient supply before birth may lead to an increased risk of obesity in later life.en
dc.format.extent2425929 bytesen
dc.format.extent141837 bytesen
dc.subjectfetal growth, lambs growth, human obesityen
dc.titleMaternal overnutrition and the regulation of energy balance and appetite before and after birthen
dc.contributor.schoolSchool of Molecular and Biomedical Scienceen
dc.provenanceThis electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exception. If you are the author of this thesis and do not wish it to be made publicly available or If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
dc.description.dissertationThesis (Ph.D.)--University of Adelaide, School of Molecular and Biomedical Science, 2006.en
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