Previous studies have suggested that the peptide galanin (GAL) in the hypothalamus is related to the preference of an animal for dietary fat. The present report investigates this relationship further to identify the specific GAL-synthesizing cell groups involved and to characterize their association to circulating glucose or hormones and their possible contribution to body fat deposition. Male albino Sprague Dawley rats were tested in different feeding paradigms with diets containing the macronutrients, fat, carbohydrate, or protein. These studies, using multiple techniques, identify a cell group in the hypothalamus that expresses GAL and that shows a shift in peptide activity in close relation to dietary fat, circulating glucose, and body fat. In all paradigms, a rise in fat intake, from 10 to 30%, is associated with reduced levels of insulin and corticosterone and normal glucose levels, whereas a further increase in fat ingestion (Ͼ30%) leads to hyperglycemia along with greater adiposity. In the hypothalamus, GAL gene expression, peptide production, and peptide release rise significantly (by 40%) in association with fat ingestion, showing no relation to either carbohydrate or protein ingestion. This change is highly site specific, evident predominantly in GAL-synthesizing neurons in the anterior parvocellular region of the paraventricular nucleus (aPVN) and in GAL-containing terminals in the external zone of the median eminence (ME). Positive correlations detected between mRNA abundance in the aPVN and GAL peptide in the ME support the existence of an aPVN-ME projection system related to fat intake and fat deposition. When activated by dietary fat, the contribution of this projection to body fat is suggested by consistent positive correlations between aPVN-ME GAL and either dietary fat, circulating glucose, or body fat and by significantly higher GAL levels (ϩ30%) in obesity-prone compared with obesity-resistant rats. This evidence supports a role for this hypothalamic GAL projection system in the development of obesity produced by the overconsumption of fat.
The physiological function of the peptde galanin (Gal) remains to be established. It is known to exist in high concentrations within the hypothalamus and to modulate the secretion of specific hormones, as well as to potentiate food consumption. Our study provides evidence for an e al function of neuronal Gal, within a specific hypothalamic area, in stimulating the behavioral process of fat ieston and body weight gain. The peptide galanin (Gal), first isolated from porcine intestine (1), consists in most species of a 29-amino acid chain that is amidated at the C terminal. Human Gal is exceptional in not being amidated and consisting of 30-amino acid residues (2). This peptide is densely concentrated in the brain (3), and within the hypothalamus, there are high levels of Gal peptide and mRNA, as well as a high density of putative high-affinity Gal receptor sites (4,5).The physiological function of neuronal Gal in the hypothalamus has not been established. It has been suggested to be endocrine in nature, based on the findings that central Gal injections alter circulating hormone levels, elevating growth hormone and prolactin, and reducing insulin and the pituitary-adrenal hormones adrenocorticotropin and corticosterone (6, 7). Although there exists little information on the behavioral actions of this peptide, the one behavior linked to hypothalamic Gal is feeding behavior (8, 9). Direct hypothalamic injections of this peptide strongly increase food intake in satiated animals, and the first 16 N-terminal amino acids contain the Gal agonist activity for this phenomenon, as well as for binding to hypothalamic Gal receptors (10,11). An important finding is the behavioral specificity of the action of Gal. In animals maintained on separate macronutrient diets, this specificity is reflected in a potent and preferential effect of Gal on fat consumption; there is a smaller effect or no impact on carbohydrate or protein intake, respectively (12). Together with the inhibitory effect ofGal injections on energy expenditure (13), this selective enhancement of fat ingestion suggests a function for hypothalamic Gal in maintaining normal energy or fat balance and possibly body weight gain.Although several neurochemicals in the brain have been suggested to have a role in feeding behavior (9), this proposal has been based predominantly on pharmacological evidence or on biochemical studies of either food-deprived or genetically obese rats on mixed diets. The possibility that endogenous Gal may be linked to the specific behavior of fat ingestion is suggested by the evidence of nutrient selectivity in its feeding-stimulatory action (12) and by the recent finding that hypothalamic administration of a specific Gal antagonist potently and selectively inhibits spontaneous consumption of fat (14). If endogenous Gal in a particular brain area can be identified as a biological "marker" for fat ingestion, this finding would lay the foundation for further studies of regulatory factors that enhance or inhibit expression of the Gal gene an...
The Diamond Princess cruise ship has been anchored at the Yokohama port in Japan since February 3, 2020. A total of 691 cases of the coronavirus disease 2019 (COVID-19) infection had been confirmed as of February 23. The government initially assumed that the infection was not spreading aboard and therefore indicated that any persons who either tested negative for the virus or were asymptomatic should immediately disembark. However, on February 5, the government set a 14-day health observation period because of the severity of the infection. Passengers confirmed to be free from infection began disembarking on Day 15 (February 19) of the quarantine. The effectiveness and validity of infection control, justification for the timing of inspections, and even the nature of COVID-19 itself now are all in question. The ethical considerations related to cruise ship infection control include the reasonable justification for isolation, the psychological fragility and quality of life of the isolated passengers and crew members, the procedural justice inherent in a forced quarantine, and the optimization of control measures. The international coordination framework and the global ramifications of such outbreaks should be reevaluated by the international community. Denying a ship's entry based on local politics is incompatible with global justice. Events such as these require an international response and global regulations that seek to reduce disparities.
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