Interactions between hypothalamic neurotransmitters and circulating steroid hormones in the control of nutrient intake.
Item
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Title
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Interactions between hypothalamic neurotransmitters and circulating steroid hormones in the control of nutrient intake.
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Identifier
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AAI9304739
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identifier
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9304739
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Creator
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Tempel, Donna Lynn.
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Contributor
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Adviser: Victoria Luine
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Date
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1992
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological | Psychology, Behavioral | Psychology, Experimental
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Abstract
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The control of food intake in rats as well as in humans involves both peripheral and central factors including transmitters, hormones and circadian timing systems. It is known that certain transmitters and peptides specifically within the hypothalamus have profound effects on nutrient intake, body weight regulation and metabolism. Specifically, within the paraventricular nucleus (PVN), norepinephrine (NE), neuropeptide Y (NPY) and galanin (GAL) are all found to stimulate food intake. In addition, the glucocorticoid corticosterone (CORT) and recently, the mineralocorticoid aldosterone (ALDO), have been shown to be involved in body weight regulation and food intake. These steroid hormones are found to interact with the above mentioned feeding stimulatory neurochemicals and act through one of two steroid receptor systems within the brain.;These experiments, using a combination of surgical, pharmacological and behavioral techniques, were performed to help define the functional role of endogenous circulating adrenal steroid hormones and their receptor systems in normal feeding behavior as well as in transmitter-stimulated feeding in the rat.;Results indicate that corticosterone (CORT), acting through the type II receptor, within the PVN, is important in the control of natural feeding, specifically the natural preference for carbohydrate seen in normal rats at the onset of the active feeding cycle. This is in contrast to aldosterone, which acts through the type I mineralocorticoid receptors to cause an increase in fat ingestion.;The type II steroid receptor, in the PVN also appears to regulate the feeding effects of NE and NPY, which after PVN injection stimulate food intake by specifically increasing carbohydrate ingestion. Injection of GAL into the PVN, which, like aldosterone, increases fat intake appears to function independent of the adrenal steroids and their receptors within the PVN.;It is suggested that PVN NE and NPY, in conjunction with circulating CORT acting through the type II PVN steroid receptor, play an important role in the feeding which occurs at dark onset and is characterized by a specific increase in carboyhdrate intake. Galanin as well as aldosterone, which may function through different mechanisms, may play a role in the regulation of fat ingestion across the feeding cycle.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
