Allen S. Levine

Bio: Allen S. Levine is an academic researcher from University of Minnesota. The author has contributed to research in topics: (+)-Naloxone & Opioid peptide. The author has an hindex of 85, co-authored 405 publications receiving 23687 citations. Previous affiliations of Allen S. Levine include Louisiana State University & Veterans Health Administration.

Effects of intracerebroventricular injection of neuropeptide Y on energy metabolism

Abstract: Our objective was to find out if central injection of neuropeptide Y (NPY) would alter brown fat thermogenesis and white fat lipoprotein lipase activity. The following three groups of Sprague-Dawley rats received five injections over 24 h into the right lateral ventricle: 1) NPY (5 micrograms/injection) and ad libitum food; 2) NPY (5 micrograms/injection) and food restricted to control intake; 3) saline injection and ad libitum food. The NPY ad libitum-fed group consumed more food than the saline controls or NPY food-restricted animals. Brown fat thermogenic activity, assessed by GDP binding, was decreased relative to saline controls in both NPY-treated groups. White fat lipoprotein lipase activity was greatly increased in both NPY treatment groups compared with saline controls. The NPY effects on brown and white fat were not explained by measures of serum insulin, glucagon, glucose, or other metabolites. In a follow-up experiment, we asked whether food was necessary for expression of the NPY effects. Brown fat mitochondrial GDP binding indicated NPY effect even when no food was ingested. We conclude that intracerebroventricular administration of NPY promotes white fat lipid storage and decreases brown fat thermogenesis in addition to its known effect of stimulating food intake.

How do glucocorticoids influence stress responses? Integrating permissive, suppressive, stimulatory, and preparative actions.

Abstract: The secretion of glucocorticoids (GCs) is a classic endocrine response to stress. Despite that, it remains controversial as to what purpose GCs serve at such times. One view, stretching back to the time of Hans Selye, posits that GCs help mediate the ongoing or pending stress response, either via basal levels of GCs permitting other facets of the stress response to emerge efficaciously, and/or by stress levels of GCs actively stimulating the stress response. In contrast, a revisionist viewpoint posits that GCs suppress the stress response, preventing it from being pathologically overactivated. In this review, we consider recent findings regarding GC action and, based on them, generate criteria for determining whether a particular GC action permits, stimulates, or suppresses an ongoing stressresponse or, as an additional category, is preparative for a subsequent stressor. We apply these GC actions to the realms of cardiovascular function, fluid volume and hemorrhage, immunity and inflammation, metabolism, neurobiology, and reproductive physiology. We find that GC actions fall into markedly different categories, depending on the physiological endpoint in question, with evidence for mediating effects in some cases, and suppressive or preparative in others. We then attempt to assimilate these heterogeneous GC actions into a physiological whole. (Endocrine Reviews 21: 55‐ 89, 2000)

Central nervous system control of food intake

Abstract: New information regarding neuronal circuits that control food intake and their hormonal regulation has extended our understanding of energy homeostasis, the process whereby energy intake is matched to energy expenditure over time. The profound obesity that results in rodents (and in the rare human case as well) from mutation of key signalling molecules involved in this regulatory system highlights its importance to human health. Although each new signalling pathway discovered in the hypothalamus is a potential target for drug development in the treatment of obesity, the growing number of such signalling molecules indicates that food intake is controlled by a highly complex process. To better understand how energy homeostasis can be achieved, we describe a model that delineates the roles of individual hormonal and neuropeptide signalling pathways in the control of food intake and the means by which obesity can arise from inherited or acquired defects in their function.

Brown Adipose Tissue: Function and Physiological Significance

Abstract: Cannon, Barbara, and Jan Nedergaard. Brown Adipose Tissue: Function and Physiological Significance. Physiol Rev 84: 277–359, 2004; 10.1152/physrev.00015.2003.—The function of brown adipose tissue i...